S-functions
           “The S-parameters
      for nonlinear components”

      - Measure, Model, Verify,
                  Simulate -


An application in ICE


                                  March 2011
Outline
     ●   Why S-functions? What is the impact?
     ●   S-functions, the “S-parameters” for all nonlinear applications?
     ●   S-functions: Key Benefits
     ●   Theory: from S-parameters to S-functions
     ●   Applicability and Assumptions of S-functions
     ●   Confidence in S-functions
     ●   S-function Extraction and Verification Tool
     ●   Deployment of S-functions in ADS and MWO / VSS
     ●   Strengths and Key Capabilities
     ●   References
     ●   Conclusion




© 2011                                                                     2
Why S-parameters?
DESIGN
     ●   Complete characterization of a component in linear mode of operation
         ●   Derive insertion loss, return loss, gain, …

     ●   S-parameters enable system-level interpretation of behavior of the
         component
         ●   Low – pass filtering, high reflective, ...

     ●   S-parameters enable design in conjunction with other circuits

TEST in Manufacturing
     ●   S-parameters can be extracted for the designed circuit

     ●   The S-parameters can be measured for the manufactured circuit and can
         be compared

S-parameters close the characterization, design and test loop


© 2011                                                                   3
S-parameter Design- and Test-Cycle for Linear Applications

  At the Foundry




                                             Design kit
                                             Design library

         Passive                             [S-parameter based]
                      S-parameters
         Devices




                                         Semiconductor Manufacturer




© 2011                                                4
S-parameter Design- and Test-Cycle for Linear Applications

  At the Semiconductor Manufacturer




         Design                 Chips              S-parameters Design kit
                                                                Design library

                                                                 [S-parameter based]
                  Iterations almost completely eliminated




                                  Design Houses               System Manufacturers


© 2011                                                                 5
Beyond S-parameters???
     ●   S-parameters, the behavioural model for “linear” applications

         ●   Components in linear mode of operation only
             ●   Filters
             ●   Transistors under small signal of excitation
             ●   ...

         ●   Their success is based on its uniform approach for linear RF and microwave
             problems both to measure and to simulate

     ●   What about components in nonlinear mode of operation?

         ●   No uniform approach for nonlinear RF and microwave problems

         ●   There is a lot of “trial and error” or “measure – tweak”

         ●   S-parameters are used mainly during device modelling in conjunction with a lot of
             model expertise to go from small-signal to large-signal

© 2011                                                                         6
“Trial-Error” Design- and Test-Cycle for “Nonlinear” Applications

  At the Foundry




                                                Design kit
                                                Design library
                             Modelling
         Devices             (6 months)

                           Small-Signal
                           Large-Signal
                           Load-Pull
                           Mathematics...

                                            Semiconductor Manufacturer




© 2011                                                   7
“Trial-Error” Design- and Test-Cycle for “Nonlinear” Applications

  At the Semiconductor Manufacturer        ● Models do not meet the needs of application
                                           ● To time costly to develop own models
                                           ● Wafer fabs cannot worry about specific problems




         Initial            Chips                                             DataSheet
         Design                                                               Eval Board

                                      Trial and Error




                              Design Houses                    System Manufacturers


© 2011                                                                    8
The Magic ...



                   S-Parameters


                       S-


                  S-functions
© 2011                            9
The S-function Design- and Test-Cycle for Active Devices

  At the Foundry




                                                  Design kit
                                                  Design library

                                                  [S-functions based (*)]
           Devices              S-Functions




                                              Semiconductor Manufacturer


(*) S-functions for different applications
© 2011                                                    10
The S-function Design- and Test-Cycle for Active Devices

  At the Semiconductor Manufacturer


             Improving S-functions with application-specific information




         Design                    Chips                S-functions          Design kit
                                                                             Design library

                                                                             [S-functions based]
                  Reducing the number of iterations




                                      Design Houses                        System Manufacturers


© 2011                                                                            11
Why S-functions? Adopting the S-parameter paradigm
DESIGN
   ● “Complete” characterization of a component in nonlinear mode of operation
     for specific applications under a relevant set of conditions
         ●   Derive “insertion loss”, “return loss”, “gain”, “mismatch”, conversion coefficients

     ●   S-functions enable system-level interpretation of behaviour of the
         component
         ●   Power- dependent Low – pass filtering, power conversions, …
         ●   Ideal for dividers, multipliers and mixers

     ●   S-functions enable design in conjunction with other circuits
         ●   When the signals are limited to the relevant set of conditions

TEST in Manufacturing
   ● S-functions can be extracted for the designed circuit

     ●   The S-functions can be measured for the manufactured circuit and can be
         compared
S-functions close the characterization, design and test loop
© 2011                                                                            12
S-Functions, the “S-parameters” for nonlinear applications?
      ●   S-Functions, the behavioural model for nonlinear applications

          ●   Deal with a subset of nonlinear RF and microwave phenomena in a uniform way
              as a natural extension of S-parameters

          ●   Will not solve “all” nonlinear problems



                                        S-parameters          Linear
                                                            Applications         All
                                                                               Other
                                                                            Applications
                                        S-functions         NonLinear (*)
                                                            Applications

          ●   Can be “measured”
                                                                                 How to define the
                                                                                 application boundary?
          ●   Can be used for design in simulators

          ●   Can be used for test to compare with realizations in simulator
(*): Nonlinear behaviour determined by a small number (e.g. 2) of tones
© 2011                                                                                     13
S-Functions – Key Benefits

   S-Functions are for nonlinear applications ...
              ... what S-parameters are for linear applications


     ●   Simplify the use of HF components and circuits
         ●   Complement limited data sheets with more complete system-level models
         ●   Complement evaluation boards, enabling upfront more realistic simulations



     ●   Improve and speed up the design and test process
         ●   Adequate replacement when classic models fail
         ●   Simulate with a behavioural model, optimized for your design problem
         ●   Same Look and Feel as S-parameters: measure, model, verify and simulate
         ●   Verify the realized circuit with S-functions against the simulation during test

     ●   Shorter time to market for component manufacturers and buyers

© 2011                                                                           14
From S-parameters to S-functions
                         S-parameters measured at fixed DC bias point
                                                    S f 
                                                          VDC
                                         f                          f
                                                             IDC

                                                                                 Keep signal small to
                                                                f                stay in a linear mode
                                                                                 of operation




                        S-parameters measured at different DC bias points
                           Linear                   S V DC ; f 
                           Nonlinear                 I DC V DC 
Remark: for the sake of intuitive explanation, mathematics is not 100% correct
© 2011                                                                                15
From S-parameters to S-functions
                                                     f0       2f
                                                                   0
                                                                       3f
                                                                            0


                      f0
                           A1  f 0           VDC
                                                          B2 k f 0 k : 1... 3 ...
               f0
                             B1 k f 0                   A2=0
                                                                                50
                                    k : 1... 3 ...
                             f0
                                 2f 3f
                                   0     0




   Simple model and “easy” to measure

                 Nonlinear              Bm n f 0=F mn V DC , f 0 ,∣a 1  f 0∣
                 Nonlinear              I DC =H V DC , f 0 ,∣a 1  f 0 ∣

© 2011                                                                                16
From S-parameters to S-functions

                                         Simple model and “easy” to measure

                                                 Bm n f 0=F mn V DC , f 0 ,∣a 1  f 0∣
                                                 I DC =H V DC , f 0 ,∣a 1  f 0 ∣
                                                              ● AM-AM
                                                              ● AM-PM

                                                              ● Harmonic Distortion




  But not useful in the real world
          ●   S-functions should be able to predict cascades

                                                           Input contains harmonics !!

              “Easy” to measure .... not in reality           f0                     A1  k f 0
                                                                   2f
          ●

                                                                        0   3f
                                                                                 0
                   ● Harmonic distortion of source                                   A2 l f 0
                   ● Imperfect match at input and output



© 2011                                                                                17
From S-parameters to S-functions
                            A1  k f 0                         f0       2f       3f
                       f0                                                     0        0
                                                                                           B2 k f 0
                                  2f
                                       0
                                            3f            VDC
                                                 0


               f0                                                                                 k : 1... 3 ...
                            B1 k f 0                               A2 k f 0 
                                                                                             ZL
                                                                f0
                             f0
                                       2f        3f                      2f       3f
                                            0         0                       0        0




                             Bm n f 0=F mn V DC , f 0 ,∣a 1  f 0∣
                             I DC =H V DC , f 0 ,∣a 1  f 0 ∣
         “Simple” model extension

          Bm n f 0=F mn V DC , f 0 ,∣a i  j f 0 ∣ , all phase comb of ai  j f 0
          I DC =H V DC , f 0 ,∣a i  j f 0∣ , all phase comb of  ai  j f 0 
© 2011                                                                                              18
From S-parameters to S-functions

         Bm n f 0=F mn V DC , f 0 ,∣a i  j f 0 ∣ , all phase comb of ai  j f 0
         I DC =H V DC , f 0 ,∣a i  j f 0∣ , all phase comb of  ai  j f 0 


         Huge number of combinations with sweeps in amplitude and phase




© 2011                                                                         19
From S-parameters to S-functions


                                                                     What now ???


f0                                                           f0        2f
                                                                            0
                                                                                3f
                                                                                     0
          2f       3f
               0        0                  VDC
                            A1  k f 0          B 2  k f 0
     f0
                             B1 k f 0     f0   A2 k f 0             ZL
                    f0
                            2f 3f                  2f       3f
                              0    0                    0        0




© 2011                                                                                   20
From S-parameters to S-functions

    f0                                                           f0      2f
                                                                              0
                                                                                   3f
                                                                                        0
              2f       3f
                   0        0                  VDC
                                A1  k f 0          B 2  k f 0
         f0
                                 B1 k f 0     f0   A2 k f 0           ZL
                        f0
                                2f 3f                  2f       3f
                                  0    0                    0        0




   In many cases : A1  k f 0 , A2 k f 0  with k 1                            SMALL


                       Linearize equations in A1  k f 0 , A2 k f 0  with k 1



© 2011                                                                                      21
From S-parameters to S-functions
The intuitive approach


            f0                                              f0   2f
                                                                      0
                                                                          3f
                                                                               0

                                             VDC
                              A1  f 0            B2  k f 0
                 f0
                               B1 k f 0     f0   A2  f 0      ZL
                         f0
                              2f 3f
                                0    0




© 2011                                                                             22
From S-parameters to S-functions



         f0                                                    f0   2f
                                                                         0
                                                                             3f
                                                                                  0
                   2f
                        0                       VDC
                                 A1  k f 0          B2  k f 0
              f0
                                  B1 k f 0     f0   A2  f 0      ZL
                            f0
                                 2f 3f
                                   0    0




© 2011                                                                                23
From S-parameters to S-functions


                                                                           x2
         f0                                                           f0        2f       3f
                   2f                                                                0        0
                        0
                            x2                        VDC
                                      A1  k f 0            B2  k f 0
              f0
                                       B1 k f 0       f0   A2  f 0           ZL
                                 f0
                   x2                 2f 3f
                                        0    0




                                                 LINEAR
                                                 But with frequency conversion, like a mixer


© 2011                                                                                            24
From S-parameters to S-functions



         f0                                                        f0   2f
                                                                             0
                                                                                 3f
                                                                                      0
                   2f       3f
                        0        0                  VDC
                                     A1  k f 0          B2  k f 0
              f0
                                      B1 k f 0     f0   A2  f 0      ZL
                             f0
                                     2f 3f
                                       0    0




                                                LINEAR Superposition


© 2011                                                                                    25
From S-parameters to S-functions



         f0                                                       f0    2f
                                                                             0
                                                                                 3f
                                                                                      0
                   2f       3f
                        0        0                  VDC
                                     A1  k f 0          B2  k f 0
              f0
                                      B1 k f 0     f0   A2 k f 0     ZL
                             f0
                                     2f 3f                 2f
                                       0    0                 0




© 2011                                                                                    26
From S-parameters to S-functions



         f0                                                       f0    2f
                                                                             0
                                                                                 3f
                                                                                      0
                   2f       3f
                        0        0                  VDC
                                     A1  k f 0          B2  k f 0
              f0
                                      B1 k f 0     f0   A2 k f 0     ZL
                             f0
                                     2f 3f                 2f 3f
                                       0    0                0     0




© 2011                                                                                    27
From S-parameters to S-functions
The Mathematical Approach
             Bm n f 0=F mn V DC , f 0 ,∣a i  j f 0 ∣ , all phase comb of ai  j f 0
             I DC =H V DC , f 0 ,∣a i  j f 0∣ , all phase comb of  ai  j f 0 

                           Linearization


  The S-functions

                                                                                                   *
  I DC =Sf 0001 V DC , A11 , A21 Sf 00ij V DC , A11 , A21  Aij Sfc 00ij V DC , A11 , A21  Aij
                                                                                                        *
  Bmn =Sf mn01 V DC , A11 , A21 Sf mnij V DC , A11 , A21 Aij Sfc mnij V DC , A11 , A 21 Aij
                             “LSOP”
   Sf mnij                                                            “Tickle tone”
             m: output port                        with j 1
             n: frequency at output port m
             i: input port                          with B mn≡B m n f 0 
             j: frequency at input port i
                                                    with Aij ≡ Ai  j f 0 
   LSOP: large-signal operating point                    Sweep in strongly reduced LSOP
© 2011                                                                             28
Sfc ???



            f0                                                    f0   2f
                                                                            0
                                                                                3f
                                                                                     0
                      2f
                           0                       VDC
                                    A1  k f 0          B2  k f 0
                 f0
                                     B1 k f 0     f0   A2  f 0      ZL
                               f0
                                    2f 3f
                                      0    0




© 2011                                                                                   29
Sfc ???



            f0                                                      f0   2f
                                                                              0
                                                                                   3f
                                                                                        0
                      2f       + df
                           0                         VDC
                                      A1  k f 0          B2  k f 0
                 f0                                                           df
                                       B1 k f 0     f0   A2  f 0      ZL
                                 f0
                                      2f 3f
                                        0    0



                                        df




© 2011                                                                                      30
Sfc ???

                                                                         *
                                                                         A
                                                                         kl

            f0                                                      f0   2f
                                                                              0
                                                                                   3f
                                                                                        0
                      2f       + df
                           0                         VDC
                                      A1  k f 0          B2  k f 0
                 f0                                                           df
                                       B1 k f 0     f0   A2  f 0         ZL
                                 f0
                                      2f 3f
                                        0    0



                                        df




© 2011                                                                                      31
How to extract S-functions?

     Select a LSOP and keep it constant


                                                                                                   *
   Bmn =Sf mn01 V DC , A11 , A21 Sf mnij V DC , A11 , A21  Aij Sfcmnij V DC , A11 , A 21  Aij
                  constant                   constant                        constant



                                                                Change the tickle tones

                                                                Measure each time Aij , B mn

     Solve for the S-functions : Sf mnij LSOP , Sfc mnij  LSOP


         Select a new LSOP and repeat


© 2011                                                                           32
Extract S-functions for a real device
                                                     DC Bias                                           f0

    f0                                                                                            or

Large-Signal                                                Tickling
  Source                                    k f0                                                       ZL
                                                            Source



                                                                                      DC Bias
     ●   Repeat the following for all LSOPs of interest
         ●   Select tickle tones                                       Large-Signal
             ●   Large enough to be detectable                           Source            Tickling
                                                                                           Source
             ●   Small enough not to violate linearity assumption

         ●   Measure incident and reflected waves for different tickle tones

         ●   Model by solving for all Sf and Sfc

     ●   Resulting into S-functions
© 2011                                                                                33
S-functions for Real Devices with ZVxPlus




                                      Bias



                        ZVxPlus
                                              Tickling
                                              Source

         Large-Signal
           Source




© 2011                                            34
Extract S-functions for a simulated device



         Bias Settings                             Large-Signal Source Settings



                                        Tickling Source Settings

                                            Tickling
                                            Source
                                   Bias                                           Bias




                         Large-Signal
                           Source



© 2011                                                                    35
Assumptions of S-functions

                                                     VDC
                                                   v3
                                                         i3
                      a1                                                              a2
                                                    DUT
                      b1                                                              b2



                                                              `


                                      a 1 k f 0  , a 2 l f 0  with l , k ≠0,1
                  Is causing only a LINEAR perturbation on the NONINEAR behaviour




  Large-Signal Operating Point (LSOP)                                   Tickle or probing tones
         a 1  f 0 , a 2  f 0 and v dc                         a 1 k f 0  , a 2 l f 0 with l , k ≠0,1
© 2011                                                                                     36
The crucial question for S-functions


                 S-parameters       Linear
                                  Applications                All
                                                            Other
                                                         Applications
                                      Some
                  S-functions       NonLinear
                                   Applications




    Mathematically well-defined                  To what applications does it apply?
                                           a 1 k f 0  , a 2 l f 0 with l , k 1   SMALL


                                                        20 dBc down from main tone

                                             BUT

© 2011                                                                        37
Applicability of S-functions




a1                                                     a2                                a3
                              DUT X                                 DUT Y
b1                                                     b2                                b3




                Components                             Prediction
                    ● Transistors                           ● Harmonic distortion
                    ● Amplifiers                            ● AM – AM and AM – PM

                    ● Dividers                              ● Source-pull

                    ● Multipliers                           ● Load-pull

                                                            ● Modulation behaviour (*)

                                                            ● Intermodulation


(*)
      : The component is assumed to be pseudo-static
© 2011                                                                         38
S-functions in ICE(*)
         ●   Sweepable Large-Signal Operating Point (LSOP)
         ●   Auto or user-defined tickle signal level
         ●   From simple push-the-button solution to access to expert-level details
         ●   Visualization of component behaviour during data collection
         ●   Easy model verification (no EDA tool required)
         ●   Sanity checks included
         ●   Easy export to and integration in Agilent™ ADS and AWR™ MWO


         ●   Support for mismatched environments
         ●   Harmonics generated by RF sources don't cause any problem
         ●   Simple output prediction does not require EDA tool
         ●   Export to and integration in other EDA tools on request
         ●   Possible to extend the LSOP variables, e.g. temperature


  (*)
        Integrated Component Characterisation Environment


© 2011                                                                     39
Confidence in S-functions

     ●   Constantness of LSOP
         ●   All Sf, and Sfc are assumed to be extracted at fixed LSOP
             ●   e.g. variation in DC drain voltage due to changing current violates this assumption


     ●   Interpolation capability of all Sf, and Sfc
         ●   LSOP interleaving verification measurements

     ●   Linearity assumption of tickle tones
         ●   Model verification for different amplitude and phases of tickle tones




                                                              Confidence
                                    Extract
    Measure                                                    through                        Simulate
                                  S-functions
                                                              Verification



© 2011                                                                                   40
Confidence in S-functions through Verification




                                                                         ADS
                                                                         MWO




ADS: Agilent Technologies Advanced Design Systems design software
MWO: AWR Corporation's Microwave Office design software

© 2011                                                              41
S-functions for Real and Simulated Components / Circuits




                       Measurements                           Simulations
   Data Collection    on Real Devices                     On Virtual Devices
                        using ICE (*)              in Simulation Tool (ADS - MWO)



                                          Extraction


                                         S-functions


                                   S-functions Verifications


                                          Simulators
   S-functions Deployment
                                        (ADS - MWO)
© 2011                                                              42
S-functions Verification – Constantness of LSOP



                                   Select LSOP variable


                                                          Variation on
Filter for a LSOP variable                                drain bias voltage
and value




  Variation on fixed input power




© 2011                                                    43
S-functions Verification – Interpolation Capability




          verify interpolation of b2 using independent set of measurements
© 2011                                                            44
S-functions Verification – Linearity Assumption of Tickle Tones
  Large-Signal                        DC Bias                                             f0

    f0                                                                               or

Large-Signal                                Tickling
  Source                       k f0                                                       ZL
                                            Source


                                                          Small-Signal
                                                          for harmonics    DC Bias

                                      DC Bias          a 2 k f 0
  Switching Amplifier design


    L 2 f 0                                L  k f 0
    L 3 f 0
                                       a 2 2 f 0 
                                                        Still small signal?
                                       a 2 3 f 0

© 2011                                                                45
ICEBreaker – Option S-function Verification Tool


       ICEBreaker                          Predicted                        Compare
       Dataset                             ICEBreaker                       Datasets
                                           Dataset



●   Measured Data                    ●   Using S-function   ●   Derived Quantities

●   Realistic Sweep Plan                                    ●   Incident / Reflected Waves

●   Under multi-harmonic Load-Pull                          ●   Voltage and Current

                                                            ●   Absolute Error

                                                            ●   Relative Error




© 2011                                                                 46
Generation of “S-function Predicted Dataset” in ICEBreaker




Generate
S-function based
Dataset




Compare
Dataset
and
S-function based
Dataset

© 2011                                             47
Absolute Comparisons with S-function Predictions

    Quantity for
    which to compare
    measurement and                                           Idc_out
    prediction
●  Derived quantities
  ➢ Idc_out
  ➢ Gain
  ➢ Pdel_in
  ➢ Pdel_out
  ➢ PAE
  ➢ ..
  ➢ Frequency selection
●  Basic quantities
  ➢ Incident waves
  ➢ Reflected waves
  ➢ Voltages / Currents
  ➢ Frequency selection


    Measurements

    S-function
    Prediction


                          Absolute Error
    © 2011                                               48
Relative Comparisons with S-function Predictions



                                                             b_out(3f0)




●    Versus
    ➢ Harmonic index
    ➢ Harmonic refl




                       Relative Error (dB)
© 2011                                                  49
Case Study(*): EPA120B-100P

            EPA120B-100P
              • high efficiency heterojunction power FET
               •   power output: + 29.0dBm typ.
               •   power gain: 11.5dB typ. @ 12 GHz




                      Real Device                                                     Virtual Device

(*)
      : all results in this slide set are based on S-function extraction and deployment for this device
© 2011                                           © 2009 - NMDG NV                                         50
Data Collection with ZVxPlus




              LSOP               “tickle”
              sweep              settings




           detailed                detailed
          feedback                feedback
           of LSOP                 on tickle
          for actual              for actual
         measurement             measurement




© 2011                             51
Expert Details If Desired @ Data Collection



Summary




                                                 Monitor
                                                RF and DC
                                                  source
                                                 settings




                                                  Observe
                                                what happens
                                                 at the DUT



© 2011                                            52
S-functions Extraction


               S11
                                         S12




                                         S22
              S21




                                                    meaningful
                                                     complex
                     ~3 dB compression              conjugate

© 2011                                         53
S-functions Verifications – Residual Error


zoom in
on                                                                            zoom in
tickling                                                                      on result




                                                              Number of measurements
                                                              required to extract
                                                              S-functions



    amplitude of complex error for measured and predicted b2 using extraction data
 © 2011                                                               54
S-functions Verification – Interpolation Capability




          verify interpolation of b2 using independent set of measurements
© 2011                                                            55
S-functions Verifications – Constantness LSOP



                                   Select LSOP variable


                                                          Variation on
Filter for a LSOP variable                                drain bias voltage
and value




  Variation on fixed input power




© 2011                                                    56
S-functions in ADS




Acknowledgement:
With the support from Agilent Technologies providing ADS licensing

© 2011                                                               57
S-functions Useage in Agilent ADS

                 EPAClassAMediumPower.ael
                 EPAClassAMediumPower.dsn




                                                Set of equations using FDD




                                            Values of all Sf, Sfc




© 2011                                                          58
S-functions Verification in ADS - Schematic
     ●   Example: Harmonic Balance simulation with measured a1 and a2 spectra
     ●   Excitation: Sweeping through a subset of LSOP points + tickle tones
                             Measured incident waves




                                   S-function to be verified

                                          Measurements for model verification


  Access to measured data
  using DAC



  Sweeping through subset
  of LSOP and tickle tones

© 2011                                                                 59
S-functions Verification in ADS - Frequency Domain
                        Frequency = 2 GHz, VDC1= -1.3 V, VDC2= +2.0 V




     Measurements at different
      input powers than those
        which were used for
    S-functions model extraction!
         circles – measurements
         solid lines - simulations




© 2011                                                                  60
S-functions Verification in ADS - Time Domain
                                                                 circles – measurements
Frequency = 2 GHz, VDC1= -1.3 V, VDC2= +2.0 V, Pa1 = +10.0 dBm   solid lines - simulations




                                                             Saturation
                                                                      Pinch-off




© 2011                                                              61
S-functions in ADS – Modulation Prediction - Schematic
  Frequency = 2 GHz, VDC1= -1.37 V, VDC2= +4.0 V, Pa1 = +0.0 dBm – Class C




© 2011                                                              62
S-functions in ADS – Modulation Prediction - Display
  Frequency = 2 GHz, VDC1= -1.37 V, VDC2= +4.0 V, Pa1 = +0.0 dBm – Class C




© 2011                                                              63
S-functions in ADS – Source-Pull - Schematic
  Frequency = 2 GHz, VDC1= -1.37 V, VDC2= +4.0 V, Pav = +1.0 dBm – Class C




                                                          Reflection : -0.27




© 2011                                                               64
S-functions in ADS – Source-Pull - Schematic
Frequency = 2 GHz, VDC1= -1.37 V, VDC2= +4.0 V, Pav = +1.0 dBm – Class C




                               Complex Conjugate




    Measured Input Impedance

© 2011                                                              65
S-functions in MWO




Acknowledgement:
With the support from AWR providing MWO / VSS licensing

© 2011                                                    66
S-functions Usage in AWR MWO

         MDF file                                  SUBCKT
                                                   ID=S1                    BIASTEE
                                                   NET="SFUNC_Model"        ID=X2

                                                                       1   RF                2
                                                                           &          RF
                                  BIASTEE                       2          DC
                                                                                DC
                                  ID=X1                                                            PORT
                                                                                3                  P=2
                                                                                                   Z=50 Ohm
                                                                                                                    Model data
                             2              RF     1        1
                                 RF          &
                                            DC
                                      DC
         PORT_PS1                      3                                                   DCVS               ..
         P=1
         Z=50 Ohm
                                                                                           ID=V2              ..
                                                                                           V=6 V
         PStart=PinMin dBm                                                                                    1.16226472890446E-16,-1.35308431126191E-16
         PStop=PinMax dBm
         PStep=PinStep dB
                                                                                                              -3.15025783237388E-15,4.72191730160887E-15
                                                 DCVS
                                                 ID=V1                                                        9.71445146547012E-17,-2.37310171513627E-15
                                                 V=-1.8 V                                                     1.51267887105178E-15,1.07899800205757E-15
                                                                                                              -2.98198965520413E-15,1.59594559789866E-15
                                                                                                              -5.759281940243E-16,-1.97758476261356E-16
                                                                                                              -1.83880688453542E-15,1.92901250528621E-15
                                                                                                              -5.06539254985228E-16,2.94209101525666E-15
                                                                                                              -2.50494069931051E-15,-6.73072708679001E-16
                                                                                                              -8.60422844084496E-16,2.65412691824451E-16
                                                                                                              -2.019218126037E-15,2.7373936450914E-15
                                                                                                              -2.28289609438548E-15,1.70870262383715E-15
                                                                                                              1.08246744900953E-15,-6.78276879106932E-16
                                                                                                              -1.02955838299224E-15,-1.31578775652841E-15
                                                                                                              5.45570533194706E-16,3.99333344169861E-15
                                                                                                              -3.62904151174348E-15,-1.74860126378462E-15
                                                                                                              -2.00100352953925E-15,-5.68989300120393E-16
                                                                                                              2.14975606760426E-15,-5.53376788836601E-16
                                                                                                              -1.16226472890446E-15,-2.44942954807925E-15
                                                                                                              2.08166817117217E-16,2.4980018054066E-15
                                                                                                              1.04372118124342E-05,-1.36061371223614E-05
                                                                                                              2.85882428840978E-15,3.11556336285435E-15
                                                                                                              -2.15105711021124E-16,1.37390099297363E-15
                                                                                                              9.71445146547012E-16,9.95731275210687E-16
                                                                                                              -1.69309011255336E-15,2.33146835171283E-15
                                                                                                              4.27435864480685E-15,3.3584246494911E-15
                                                                                                              -1.08246744900953E-15,-8.60422844084496E-16
                                                                                                              …
                       2D and 3D package data


© 2011                                                                                                                                   67
S-functions Verification in MWO - Frequency Domain

                                                                                                  HBT UNER2
                                                                                                  ID=X1
                                                                                                  Mag1=0
                                                                                                  Ang1=0 Deg
                                                                                                  Mag2=0
                                                                                                  Ang2=0 Deg
                                                                                                  Mag3=0
                                                                                                  Ang3=0 Deg
                                                                                                  Fo=2 GHz
                                                                                                  Zo=50 Ohm
                    PORT _PS1
                    P=1                                                                      1                    2
                    Z=50 Ohm
                    PStart=-20 dBm        BIAST EE                        2
                    PStop=8 dBm           ID=X2                                                                       PORT
                    PStep=1 dB                                                                          3:Bias        P=2
                                                                              SUBCK T
                                     2             RF     1           1                                               Z=50 Ohm
                                         RF         &                         ID=S1
                                                   DC                         NET ="EPA_120_B "
                                              DC
                                               3                                                               DCVS
                                                                                                               ID=V1
                                                                                                               V=DC2val V



                                                        DCVS
                                                        ID=V2
                                                        V=DC 1val V




                                                   Po with swept Pin                                                                                                                    Gain and Phase with swept Pin
  40                                                                                                                                             20
                                                                                                                                                19.5
  20                                                                                                                                             19
                    F0                                                                                                                          18.5
                                                                                                                                                             DB(|LSSnm(PORT_2,PORT_1,1,1)|)[1,X]
   0                                                                                                                                             18          Swept Power.AP_HB

                                                                                                                                                             Ang(LSSnm(PORT_2,PORT_1,2,1))[1,X] (Deg)
                                                                                                                                                17.5         Swept Power.AP_HB


  -20                                                                                                                                            17
                                                                                                                                                150
                                         2F0
  -40                                                                                                                                           100
                                                                                                        DB(|Pcomp(PORT_2,1)|)[1,X] (dBm)
                                                                                                        Swept Power.AP_HB
                                                                                                                                                 50
                                                     3F0                                                DB(|Pcomp(PORT_2,2)|)[1,X] (dBm)
  -60                                                                                                   Swept Power.AP_HB
                                                                                                        DB(|Pcomp(PORT_2,3)|)[1,X] (dBm)
                                                                                                        Swept Power.AP_HB
                                                                                                                                                  0

  -80                                                                                                                                           -50
        -20   -15                    -10                       -5                                   0                            5         10          -20            -15                     -10           -5             0   5   10
                                                           Power (dBm)                                                                                                                                  Power (dBm)




© 2011                                                                                                                                                                                                                68
S-functions Verification in MWO - Time Domain

                                                                                                                                            Vtime(V_METER.VM1,1)[*,T] (V)           Itime(I_METER.AMP1,1)[*,T] (mA)
                                                                                        HBTUNER2                                            Waveform Tests.AP_HB                    Waveform Tests.AP_HB
                                                                                        ID=X1
                                                                                        Mag1=0
                                                                                        Ang1=0 Deg
                                                                                        Mag2=0
                                                                                        Ang2=0 Deg
                                                                                        Mag3=0
                                                                                                                                                                               IV
                                                                                        Ang3=0 Deg                                    250
                                                                                        Fo=2 GHz
                                      SUBCKT                                            Zo=50 Ohm
  PORT_PS1                            ID=S1                                                                                           200
  P=1                                 NET="EPA_120_B"                              1                      2
  Z=50 Ohm
  PStart=-20 dBm        BIASTEE                         2                                                                             150
  PStop=8 dBm           ID=X2                                                                              PORT
  PStep=1 dB                                                     I_METER                       3:Bias P=2
                   2             RF     1   1                    ID=AMP1                                   Z=50 Ohm                   100
                       RF         &
                                 DC
                            DC                                                                                                          50
                             3                                       V _METER                        DCVS
                                                                     ID =VM1                         ID=V1
                                                                                                     V=DC2val V
                                                                                                                                         0
                                                                                                                                        15
                                      DCVS
                                      ID=V2
                                      V=DC1val V
                                                                                                                                        10


                                                                                                                                           5

                                                DB(|Pcomp(PORT_2,1)|)[1,X] (dBm)   DB(|Pcomp(PORT_2,2)| )[1,X] (dBm)   DB(|Pcomp(PORT_2,3)|)[1,X] (dBm)
                                                Waveform Tests.AP_HB               Waveform Tests.AP_HB                Waveform Tests.AP_HB0
                                                                                                                                                0         0.2        0.4                0.6        0.8           1
                                                                                              Harmonics
                                                40                                                                                                                          Time (ns)

                                                20


                                                   0


                                                -20


                                                -40


                                                -60


                                                -80
                                                       -20                             -10                             0                            8
                                                                                             Power (dBm)




© 2011                                                                                                                                                                                          69
S-functions in MWO – Modulation Prediction - Schematic
                                                                                                                                                                                                 DB(PWR_SPEC(TP.AMP Out,1000,0,10,0,-1,0,-1,1,0,4,0,1,0)) (dBm)     DB(PWR_SPEC(TP.AMP In,1000,0,10,0,-1,0,-1,1,0,4,0,1,0)) (dBm)
                                                                                                                                                                                                 16QAM System                                                       16QAM System
                                                                                                          HBTUNER2
                                                                                                          ID=DCBlock2
                                                                                                          Mag1=0
                                                                                                          Ang1=0 Deg
                                                                                                          Mag2=0
                                                                                                          Ang2=0 Deg
                                                                                                          Mag3=0                                                                                                                                                  ACPR
                                                                       SUBCKT
                                                                                                          Ang3=0 Deg
                                                                                                          Fo=2000 GHz                                                                                  50
                                                                       ID=S1                              Zo=50 Ohm
                            ISOL8R                                     NET="EPA_120_B"
                            ID=U1                                                                     1                        2
                            R=50 Ohm
                            LOSS=0 dB                 BIASTEE                                2
                            ISOL=30 dB                ID=X1                                                                    PORT
                                                                                                                  3:Bias P=2
                                                 2
                                                     RF
                                                               RF
                                                                &
                                                                      1              1                                         Z=50 Ohm                                                                   0
                                                               DC
                                                          DC
         PORT_PS1                                          3                                                              DCVS
         P=1                                                                                                              ID=V3
         Z=50 Ohm                                                                                                         V=DC2val V
         PStart=-20 dBm
         PStop=8 dBm
         PStep=0.5 dB
                                                                    DCVS
                                                                                                                                                                                                     -50
                                                                    ID=V1
                                                                    V=DC1val V




                                                                                                                                                                                                  -100



                                                                                                                                                                                                  -150
                                                                                                                                                                                                               1.92   1.94           1.96          1.98      2      2.02                    2.04           2.06           2.08
                                                                                                                                                                                                                                                      Frequency (GHz)




                                                                      VS A
                                                                      ID=M1
                                                                      VA RNA ME=""
                                                                      VA LUE S=0
                                                                      NA VG=

     PBA SE = -76                                                                        V e c to r
     S w e p t v a r ia b le                                                             S ig n a l
                                                                     SRC    MEAS
                                                                                         A n a ly z e r
     QAM_S RC                                                                                                                                        G e n e r a l R e c e iv e r
     ID=A1
     MO D=16-QA M (Gray)
     OUT LV L=-0.2
     OLVLT Y P=Avg. Power (dB m)                                NL_ S
                                                                                                           AW GN
     RAT E=_DRA T E                                             ID=S 1                                                                                                              BER
                                                                                                           ID=A3
     CTRFRQ=2 GHz                        TP                     NET ="AMAM A MPM.AP_HB "                   PW R=-170                                                                ID=5
                                                                SIMT YP=Harm onic Balanc e                                                        TP
     PLST Y P=Root Rais ed Cos ine       ID=AMP In                                                         PW RT YP=Avg. Po wer, Sym bol (dBW )                                     VARNAME="PBA SE"
                                                                                                                                                  ID=AMP Out
     ALPHA =0.35                                                NO SE=RF Budget only
                                                                   I                                                                                                                VALUES=s tepped(-76,-40,2)
                                                                                                           LOSS=0 dB
     PLSLN=                                                     RFIF RQ=                                                                                       QAM_RX               OUT FL=""
                                                                                                                                                               ID=A 2

                                                                                                                                                           1   R        D
                                                                                                                                                                            2           BER


                                                                                                                                                                    IQ      3
                                                               C irc u it                                                                                      5    4
                                                                                                                                                                                         B E R D e te c to r
                                                          B a s e d A m p lifie r                                C h a n n e l N o is e
         1 6 Q A M S o u rc e                                                                                                                                                           TP
                                                                                                                                                                                        ID=RX Cons tellation




                                                          1 6 Q A M (G r a y ) S y s te m


© 2011                                                                                                                                                                                                                                                                                   70
S-functions in MWO – Load-Pull
                                                                                                                                                                                                                                                                                                                      HBTUNER2
                                                                                                                                                                                                                                                                                                                      ID=DCBlock2
                                                                                                                                                                                                                                                                                                                      Mag1=0.8
                                                                                                                                                                                                                                                                                                                                                       Load Tuner (and bias)
                                                                                                                                                                                                                                                                                                                      Ang1=40 Deg
                                                LP_Data_Low_Power                                                                                                                                                                                                                                                     Mag2=0
                                                                                                                                                                                                                                                                                                                      Ang2=0 Deg
                                                                                           1.0                                                                             Swp Max                                                                                                                                    Mag3=0
                                                                0.8




                                                                                                                                                                                            -0.89                                                                                                                     Ang3=0 Deg
                                                                                                                                                                                                                                                                                                                      Fo=2 GHz
                                       6
                                           0.




                                                                                                                                                                                                                                                                                                                      Zo=50 Ohm




                                                                                                                                            0
                                                                                                                                        .
                                                                                                                                        2
                      4
                          .                                                                                                                                                                                                                                                                                       1                   2
                                                                                                                                                                                                                                            PORT1
                              0
                                                                                                                                                                           0
                                                                                                                                                                       .
                                                                                                                                                                   3
                                                                                                                                                                                                                                            P=1                                                  2
                                                                                                  p8                                                                                    0
                                                                                                                                                                                                         p1: Pcomp_PORT_2_1_M_DB = -2.87    Z=50 Ohm                                                                                        PORT
                                                                p7                                                                                                                 4.
                                                                                                                                                                                                                                            Pwr=10 dBm                                                                     3:Bias           P=2
                                                                                           p9                                                                                                            p2: Pcomp_PORT_2_1_M_DB = -2.65                                                             SUBCKT
                                                                                                                                                                                        5.
                                                                                                                                                                                             0
                                                                                                                                                                                                                                                               2             RF     1                                                       Z=50 Ohm
     2
                                                    p6                                                                                                                                                                                                                                       1       ID=S1
         0.
                                                                                                                                                                                                                                                                   RF         &
                                                                                            p10                                                                                                          p3: Pcomp_PORT_2_1_M_DB = -2.43                                     DC                      NET="SFUNC_Model"
                                               p5                                                                                                                                                                                                                       DC
                                                                                                                                                                                            10.
                                                                                                                                                                                                   0
                                                                                                                                                                                                                                                     BIASTEE
                                                                                                                                                                                                         p4: Pcomp_PORT_2_1_M_DB = -2.21                                 3                                                          DCVS
                                                                                                                                                                                                                                                     ID=X1
                                       p4                                                                                                                                                                                                                                                                                           ID=V2
                                                                                                                                                                           10.0

                                                                                                                                                                                                                                                                                                                                    V=7 V
                                                                                                                                            4.0




                                                                                                                                                                                                         p5: Pcomp_PORT_2_1_M_DB = -1.99
                          0.2




                                           0.4



                                                          0.6


                                                                              0.8

                                                                                            1.0




                                                                                                                  2.0



                                                                                                                                  3.0



                                                                                                                                                      5.0
 0




                                       p3
                                                                                                                                                                                                         p6: Pcomp_PORT_2_1_M_DB = -1.77                                          DCVS
                                            p2
                                                                                                                                                                                                                                                                                  ID=V1
                                                                                                                                                                                        .0
                                                                                                                                                                                                 -10     p7: Pcomp_PORT_2_1_M_DB = -1.55                                          V=-0.6 V
                                                    p1
     -0
          .
              2
                                                                                                                                                                                   0
                                                                                                                                                                                       .
                                                                                                                                                                                                         p8: Pcomp_PORT_2_1_M_DB = -1.33
                                                                                                                                                                                            -5

                                                                                                                                                                               0
                                                                                                                                                                                   .
                                                                                                                                                                                       -4
                                                                                                                                                                                                         p9: Pcomp_PORT_2_1_M_DB = -1.11
                                                                                                                                                                                                         p10: Pcomp_PORT_2_1_M_DB = -0.89
                                                                                                                                                               0
                                                                                                                                                                   .
                                                                                                                                                                       3
                                  4                                                                                                                                        -
                              .
                          0
                      -
                                                                                                                                        0
                                                                                                                                        .
                                                                                                                                            2
                                            6




                                                                                                                                            -
                                           .
                                       -0




                                                                    8




                                                                                                                                                                               Swp Min
                                                                                           -1.0
                                                                -0.




                                                                                                                                                                                            -2.87




                                                    LP_Data_High_Power
                                                                                                                                                            S M
                                                                                                                                                             wp ax
                                                                                    1.0
                                                          0 .8




                                                                                                                                                              25.93
                                      6
                                      0.




                                                                                                                              .0
                                                                                                                              2




                  .4
                          0                                                                                                                                                                            p1: Pcomp_PORT _2_1_M_DB = 21.93
                                                                                                                                                          .0
                                                                                                                                                      3


                                                             p9
                                                                        p8 p7 p6 p5                                                                                                                    p2: Pcomp_PORT _2_1_M_DB = 22.33
                                                                                                       p4                                                      4   .0


     2
                                                 p10                                                        p3                                                     5.
                                                                                                                                                                     0
                                                                                                                                                                                                       p3: Pcomp_PORT _2_1_M_DB = 22.73
         0.
                                                                                                                  p2
                                                                                                                                                                             0
                                                                                                                                                                                                       p4: Pcomp_PORT _2_1_M_DB = 23.13
                                                                                                                                                                        1 0.
                                                 p11
                                                                                                                                                                                                       p5: Pcomp_PORT _2_1_M_DB = 23.53
                                                                                                                                                            10.0
                                       0.4




                                                                        0.8




                                                                                                                        3.0
                      0.2




                                                       0.6




                                                                                    1.0




                                                                                                            2.0




                                                                                                                                  4.0
                                                                                                                                  5.0




                                                                                                                        p1
                                                                                                                                                                                                       p6: Pcomp_PORT _2_1_M_DB = 23.93
 0




                                                                                                                                                                   0            .
                                                                                                                                                                                                       p7: Pcomp_PORT _2_1_M_DB = 24.33
                                                                                                                                                                           - 10

                                                                                                                                                                                                       p8: Pcomp_PORT _2_1_M_DB = 24.73
       .2
     -0                                                                                                                                                          .0

                                                                                                                                                            .0
                                                                                                                                                               -5
                                                                                                                                                                                                       p9: Pcomp_PORT _2_1_M_DB = 25.13
                                                                                                                                                                   -4

                                                                                                                                                  0                                                    p10: Pcomp_PORT _2_1_M_DB = 25.53
                                                                                                                                                      3.
                              4                                                                                                                            -
                      0.
                  -                                                                                                                                                                                    p11: Pcomp_PORT _2_1_M_DB = 25.93
                                                                                                                              0
                                                                                                                              2.
                                      .6




                                                                                                                                  -
                                      -0




                                                          8




                                                                                                                                                               S M
                                                                                                                                                                wp in
                                                                                    -1.0
                                                         - 0.




                                                                                                                                                                 21.93




© 2011                                                                                                                                                                                                                                                                                                                                            71
S-functions Strengths
     ●   S-functions are completely public
     ●   S-functions are transparent
     ●   S-functions are connected into ADS and MWO and can be connected in
         other tools on request, e.g. Matlab
     ●   S-functions are closely integrated with load-pull in general and especially
         with tuners from Focus Microwave
     ●   S-functions extraction tool has a verification capability for LSOP
         constantness and interpolation capability, investigating quality of model,
         without needing a simulation tool
     ●   The source- and load-pull software ICEBreaker from NMDG allows S-
         function verification, related to the linearity assumption
     ●   Customers can explore the capabilities of S-functions via NMDG services




© 2011                                                                  72
S-Functions - Key Capabilities
  ●   Natural extension of S-parameters
      ●   Reduce to S-parameters for small-signal excitation
      ●   S-parameters are cascadeable, S-Functions are cascadeable too
      ●   e.g. Transistors, amplifiers, dividers, multipliers

  ●   Predict harmonic behaviour of components under different impedances
      ●   Source – Pull
      ●   Load – Pull
      ●   Harmonic distortion, Waveforms

  ●   Predict modulation behaviour of components under different
      impedances
      ●   When no long-term memory effects

  ●   Valid for multi-ports, applicable to differential components




© 2011                                                                    73
References
     ●   F. Verbeyst and M. Vanden Bossche, “VIOMAP, the S-parameter equivalent for
         weakly nonlinear RF and microwave devices”, published in the Microwave
         Symposium Digest of IEEE 1994 MTT-S International and published in the 1994
         Special Symposium Issue of the MTT Transactions, vol. 42, no. 12, pp. 2531 –
         2535.
     ●   F. Verbeyst and M. Vanden Bossche, “VIOMAP, 16QAM and Spectral Regrowth:
         Enhanced Prediction and Predistortion based on Two-Tone Black-Box Model
         Extraction”, published in the Proceedings of the 45th ARFTG Conference, Orlando,
         June 1995 and winner of the “Best Conference Paper Award”.
     ●   J. Verspecht and P. Van Esch, “Accurately characterizating of hard nonlinear
         behaviour of microwave components by the Nonlinear Network Measurement
         System: introducing the nonlinear scattering function,” Proc. International Workshop
         on Integrated Nonlinear Microwave and Millimiterwave Circuits (INMMiC), October
         1998, pp.17-26.
     ●   J. Verspecht, “Scattering functions for nonlinear behavioral modeling in the
         frequency domain,” IEEE MTT-S Int. Microwave Symp. Workshop, June 2003.
     ●   J. Verspecht and D.E. Root “Polyharmonic Distortion Modeling,” IEEE Microwave
         Magazine, vol.7 no.3, June 2006, pp.44-57.
     ●   D.E. Root, J. Horn, L. Betts, C. Gillease, and J. Verspecht, ”X-Parameters: The new
         paradigm for measurement, modeling, and design of nonlinear RF and microwave
         components,” Microwave Engineering Europe, December 2008, pp. 16-21.

© 2011                                                                       74
Conclusion
     ●   S-functions are a natural extension to S-parameters for nonlinear behaviour

     ●   S-functions aren't much more complex than S-parameters

     ●   S-functions are accurate when assumptions are not violated
         ●   Linearity assumption

     ●   S-function extraction is supported on R&S network analysers

     ●   S-functions can be coupled into ADS and MWO

     ●   S-functions can be used to compress or hide specifics of nonlinear circuits
         in ADS and MWO


   For more information         info@nmdg.be
                                www.nmdg.be

© 2011                                                                 75
Explore the power of S-functions



    Send your device or circuit to NMDG ...




                                 `
                          … and NMDG sends you the S-functions




 Please contact NMDG at   info@nmdg.be



© 2011                                                  76

S-functions Presentation: The S-parameters for nonlinear components - Measure, Model, Verify, Simulate-

  • 1.
    S-functions “The S-parameters for nonlinear components” - Measure, Model, Verify, Simulate - An application in ICE March 2011
  • 2.
    Outline ● Why S-functions? What is the impact? ● S-functions, the “S-parameters” for all nonlinear applications? ● S-functions: Key Benefits ● Theory: from S-parameters to S-functions ● Applicability and Assumptions of S-functions ● Confidence in S-functions ● S-function Extraction and Verification Tool ● Deployment of S-functions in ADS and MWO / VSS ● Strengths and Key Capabilities ● References ● Conclusion © 2011 2
  • 3.
    Why S-parameters? DESIGN ● Complete characterization of a component in linear mode of operation ● Derive insertion loss, return loss, gain, … ● S-parameters enable system-level interpretation of behavior of the component ● Low – pass filtering, high reflective, ... ● S-parameters enable design in conjunction with other circuits TEST in Manufacturing ● S-parameters can be extracted for the designed circuit ● The S-parameters can be measured for the manufactured circuit and can be compared S-parameters close the characterization, design and test loop © 2011 3
  • 4.
    S-parameter Design- andTest-Cycle for Linear Applications At the Foundry Design kit Design library Passive [S-parameter based] S-parameters Devices Semiconductor Manufacturer © 2011 4
  • 5.
    S-parameter Design- andTest-Cycle for Linear Applications At the Semiconductor Manufacturer Design Chips S-parameters Design kit Design library [S-parameter based] Iterations almost completely eliminated Design Houses System Manufacturers © 2011 5
  • 6.
    Beyond S-parameters??? ● S-parameters, the behavioural model for “linear” applications ● Components in linear mode of operation only ● Filters ● Transistors under small signal of excitation ● ... ● Their success is based on its uniform approach for linear RF and microwave problems both to measure and to simulate ● What about components in nonlinear mode of operation? ● No uniform approach for nonlinear RF and microwave problems ● There is a lot of “trial and error” or “measure – tweak” ● S-parameters are used mainly during device modelling in conjunction with a lot of model expertise to go from small-signal to large-signal © 2011 6
  • 7.
    “Trial-Error” Design- andTest-Cycle for “Nonlinear” Applications At the Foundry Design kit Design library Modelling Devices (6 months) Small-Signal Large-Signal Load-Pull Mathematics... Semiconductor Manufacturer © 2011 7
  • 8.
    “Trial-Error” Design- andTest-Cycle for “Nonlinear” Applications At the Semiconductor Manufacturer ● Models do not meet the needs of application ● To time costly to develop own models ● Wafer fabs cannot worry about specific problems Initial Chips DataSheet Design Eval Board Trial and Error Design Houses System Manufacturers © 2011 8
  • 9.
    The Magic ... S-Parameters S- S-functions © 2011 9
  • 10.
    The S-function Design-and Test-Cycle for Active Devices At the Foundry Design kit Design library [S-functions based (*)] Devices S-Functions Semiconductor Manufacturer (*) S-functions for different applications © 2011 10
  • 11.
    The S-function Design-and Test-Cycle for Active Devices At the Semiconductor Manufacturer Improving S-functions with application-specific information Design Chips S-functions Design kit Design library [S-functions based] Reducing the number of iterations Design Houses System Manufacturers © 2011 11
  • 12.
    Why S-functions? Adoptingthe S-parameter paradigm DESIGN ● “Complete” characterization of a component in nonlinear mode of operation for specific applications under a relevant set of conditions ● Derive “insertion loss”, “return loss”, “gain”, “mismatch”, conversion coefficients ● S-functions enable system-level interpretation of behaviour of the component ● Power- dependent Low – pass filtering, power conversions, … ● Ideal for dividers, multipliers and mixers ● S-functions enable design in conjunction with other circuits ● When the signals are limited to the relevant set of conditions TEST in Manufacturing ● S-functions can be extracted for the designed circuit ● The S-functions can be measured for the manufactured circuit and can be compared S-functions close the characterization, design and test loop © 2011 12
  • 13.
    S-Functions, the “S-parameters”for nonlinear applications? ● S-Functions, the behavioural model for nonlinear applications ● Deal with a subset of nonlinear RF and microwave phenomena in a uniform way as a natural extension of S-parameters ● Will not solve “all” nonlinear problems S-parameters Linear Applications All Other Applications S-functions NonLinear (*) Applications ● Can be “measured” How to define the application boundary? ● Can be used for design in simulators ● Can be used for test to compare with realizations in simulator (*): Nonlinear behaviour determined by a small number (e.g. 2) of tones © 2011 13
  • 14.
    S-Functions – KeyBenefits S-Functions are for nonlinear applications ... ... what S-parameters are for linear applications ● Simplify the use of HF components and circuits ● Complement limited data sheets with more complete system-level models ● Complement evaluation boards, enabling upfront more realistic simulations ● Improve and speed up the design and test process ● Adequate replacement when classic models fail ● Simulate with a behavioural model, optimized for your design problem ● Same Look and Feel as S-parameters: measure, model, verify and simulate ● Verify the realized circuit with S-functions against the simulation during test ● Shorter time to market for component manufacturers and buyers © 2011 14
  • 15.
    From S-parameters toS-functions S-parameters measured at fixed DC bias point S f  VDC f f IDC Keep signal small to f stay in a linear mode of operation S-parameters measured at different DC bias points Linear S V DC ; f  Nonlinear I DC V DC  Remark: for the sake of intuitive explanation, mathematics is not 100% correct © 2011 15
  • 16.
    From S-parameters toS-functions f0 2f 0 3f 0 f0 A1  f 0  VDC B2 k f 0 k : 1... 3 ... f0 B1 k f 0 A2=0 50 k : 1... 3 ... f0 2f 3f 0 0 Simple model and “easy” to measure Nonlinear Bm n f 0=F mn V DC , f 0 ,∣a 1  f 0∣ Nonlinear I DC =H V DC , f 0 ,∣a 1  f 0 ∣ © 2011 16
  • 17.
    From S-parameters toS-functions Simple model and “easy” to measure Bm n f 0=F mn V DC , f 0 ,∣a 1  f 0∣ I DC =H V DC , f 0 ,∣a 1  f 0 ∣ ● AM-AM ● AM-PM ● Harmonic Distortion But not useful in the real world ● S-functions should be able to predict cascades Input contains harmonics !! “Easy” to measure .... not in reality f0 A1  k f 0 2f ● 0 3f 0 ● Harmonic distortion of source A2 l f 0 ● Imperfect match at input and output © 2011 17
  • 18.
    From S-parameters toS-functions A1  k f 0 f0 2f 3f f0 0 0 B2 k f 0 2f 0 3f VDC 0 f0 k : 1... 3 ... B1 k f 0 A2 k f 0  ZL f0 f0 2f 3f 2f 3f 0 0 0 0 Bm n f 0=F mn V DC , f 0 ,∣a 1  f 0∣ I DC =H V DC , f 0 ,∣a 1  f 0 ∣ “Simple” model extension Bm n f 0=F mn V DC , f 0 ,∣a i  j f 0 ∣ , all phase comb of ai  j f 0 I DC =H V DC , f 0 ,∣a i  j f 0∣ , all phase comb of  ai  j f 0  © 2011 18
  • 19.
    From S-parameters toS-functions Bm n f 0=F mn V DC , f 0 ,∣a i  j f 0 ∣ , all phase comb of ai  j f 0 I DC =H V DC , f 0 ,∣a i  j f 0∣ , all phase comb of  ai  j f 0  Huge number of combinations with sweeps in amplitude and phase © 2011 19
  • 20.
    From S-parameters toS-functions What now ??? f0 f0 2f 0 3f 0 2f 3f 0 0 VDC A1  k f 0 B 2  k f 0 f0 B1 k f 0  f0 A2 k f 0  ZL f0 2f 3f 2f 3f 0 0 0 0 © 2011 20
  • 21.
    From S-parameters toS-functions f0 f0 2f 0 3f 0 2f 3f 0 0 VDC A1  k f 0 B 2  k f 0 f0 B1 k f 0  f0 A2 k f 0  ZL f0 2f 3f 2f 3f 0 0 0 0 In many cases : A1  k f 0 , A2 k f 0  with k 1 SMALL Linearize equations in A1  k f 0 , A2 k f 0  with k 1 © 2011 21
  • 22.
    From S-parameters toS-functions The intuitive approach f0 f0 2f 0 3f 0 VDC A1  f 0  B2  k f 0 f0 B1 k f 0  f0 A2  f 0  ZL f0 2f 3f 0 0 © 2011 22
  • 23.
    From S-parameters toS-functions f0 f0 2f 0 3f 0 2f 0 VDC A1  k f 0 B2  k f 0 f0 B1 k f 0  f0 A2  f 0  ZL f0 2f 3f 0 0 © 2011 23
  • 24.
    From S-parameters toS-functions x2 f0 f0 2f 3f 2f 0 0 0 x2 VDC A1  k f 0 B2  k f 0 f0 B1 k f 0  f0 A2  f 0  ZL f0 x2 2f 3f 0 0 LINEAR But with frequency conversion, like a mixer © 2011 24
  • 25.
    From S-parameters toS-functions f0 f0 2f 0 3f 0 2f 3f 0 0 VDC A1  k f 0 B2  k f 0 f0 B1 k f 0  f0 A2  f 0  ZL f0 2f 3f 0 0 LINEAR Superposition © 2011 25
  • 26.
    From S-parameters toS-functions f0 f0 2f 0 3f 0 2f 3f 0 0 VDC A1  k f 0 B2  k f 0 f0 B1 k f 0  f0 A2 k f 0  ZL f0 2f 3f 2f 0 0 0 © 2011 26
  • 27.
    From S-parameters toS-functions f0 f0 2f 0 3f 0 2f 3f 0 0 VDC A1  k f 0 B2  k f 0 f0 B1 k f 0  f0 A2 k f 0  ZL f0 2f 3f 2f 3f 0 0 0 0 © 2011 27
  • 28.
    From S-parameters toS-functions The Mathematical Approach Bm n f 0=F mn V DC , f 0 ,∣a i  j f 0 ∣ , all phase comb of ai  j f 0 I DC =H V DC , f 0 ,∣a i  j f 0∣ , all phase comb of  ai  j f 0  Linearization The S-functions * I DC =Sf 0001 V DC , A11 , A21 Sf 00ij V DC , A11 , A21  Aij Sfc 00ij V DC , A11 , A21  Aij * Bmn =Sf mn01 V DC , A11 , A21 Sf mnij V DC , A11 , A21 Aij Sfc mnij V DC , A11 , A 21 Aij “LSOP” Sf mnij “Tickle tone” m: output port with j 1 n: frequency at output port m i: input port with B mn≡B m n f 0  j: frequency at input port i with Aij ≡ Ai  j f 0  LSOP: large-signal operating point Sweep in strongly reduced LSOP © 2011 28
  • 29.
    Sfc ??? f0 f0 2f 0 3f 0 2f 0 VDC A1  k f 0 B2  k f 0 f0 B1 k f 0  f0 A2  f 0  ZL f0 2f 3f 0 0 © 2011 29
  • 30.
    Sfc ??? f0 f0 2f 0 3f 0 2f + df 0 VDC A1  k f 0 B2  k f 0 f0 df B1 k f 0  f0 A2  f 0  ZL f0 2f 3f 0 0 df © 2011 30
  • 31.
    Sfc ??? * A kl f0 f0 2f 0 3f 0 2f + df 0 VDC A1  k f 0 B2  k f 0 f0 df B1 k f 0  f0 A2  f 0  ZL f0 2f 3f 0 0 df © 2011 31
  • 32.
    How to extractS-functions? Select a LSOP and keep it constant * Bmn =Sf mn01 V DC , A11 , A21 Sf mnij V DC , A11 , A21  Aij Sfcmnij V DC , A11 , A 21  Aij constant constant constant Change the tickle tones Measure each time Aij , B mn Solve for the S-functions : Sf mnij LSOP , Sfc mnij  LSOP Select a new LSOP and repeat © 2011 32
  • 33.
    Extract S-functions fora real device DC Bias f0 f0 or Large-Signal Tickling Source k f0 ZL Source DC Bias ● Repeat the following for all LSOPs of interest ● Select tickle tones Large-Signal ● Large enough to be detectable Source Tickling Source ● Small enough not to violate linearity assumption ● Measure incident and reflected waves for different tickle tones ● Model by solving for all Sf and Sfc ● Resulting into S-functions © 2011 33
  • 34.
    S-functions for RealDevices with ZVxPlus Bias ZVxPlus Tickling Source Large-Signal Source © 2011 34
  • 35.
    Extract S-functions fora simulated device Bias Settings Large-Signal Source Settings Tickling Source Settings Tickling Source Bias Bias Large-Signal Source © 2011 35
  • 36.
    Assumptions of S-functions VDC v3 i3 a1 a2 DUT b1 b2 ` a 1 k f 0  , a 2 l f 0  with l , k ≠0,1 Is causing only a LINEAR perturbation on the NONINEAR behaviour Large-Signal Operating Point (LSOP) Tickle or probing tones a 1  f 0 , a 2  f 0 and v dc a 1 k f 0  , a 2 l f 0 with l , k ≠0,1 © 2011 36
  • 37.
    The crucial questionfor S-functions S-parameters Linear Applications All Other Applications Some S-functions NonLinear Applications Mathematically well-defined To what applications does it apply? a 1 k f 0  , a 2 l f 0 with l , k 1 SMALL 20 dBc down from main tone BUT © 2011 37
  • 38.
    Applicability of S-functions a1 a2 a3 DUT X DUT Y b1 b2 b3 Components Prediction ● Transistors ● Harmonic distortion ● Amplifiers ● AM – AM and AM – PM ● Dividers ● Source-pull ● Multipliers ● Load-pull ● Modulation behaviour (*) ● Intermodulation (*) : The component is assumed to be pseudo-static © 2011 38
  • 39.
    S-functions in ICE(*) ● Sweepable Large-Signal Operating Point (LSOP) ● Auto or user-defined tickle signal level ● From simple push-the-button solution to access to expert-level details ● Visualization of component behaviour during data collection ● Easy model verification (no EDA tool required) ● Sanity checks included ● Easy export to and integration in Agilent™ ADS and AWR™ MWO ● Support for mismatched environments ● Harmonics generated by RF sources don't cause any problem ● Simple output prediction does not require EDA tool ● Export to and integration in other EDA tools on request ● Possible to extend the LSOP variables, e.g. temperature (*) Integrated Component Characterisation Environment © 2011 39
  • 40.
    Confidence in S-functions ● Constantness of LSOP ● All Sf, and Sfc are assumed to be extracted at fixed LSOP ● e.g. variation in DC drain voltage due to changing current violates this assumption ● Interpolation capability of all Sf, and Sfc ● LSOP interleaving verification measurements ● Linearity assumption of tickle tones ● Model verification for different amplitude and phases of tickle tones Confidence Extract Measure through Simulate S-functions Verification © 2011 40
  • 41.
    Confidence in S-functionsthrough Verification ADS MWO ADS: Agilent Technologies Advanced Design Systems design software MWO: AWR Corporation's Microwave Office design software © 2011 41
  • 42.
    S-functions for Realand Simulated Components / Circuits Measurements Simulations Data Collection on Real Devices On Virtual Devices using ICE (*) in Simulation Tool (ADS - MWO) Extraction S-functions S-functions Verifications Simulators S-functions Deployment (ADS - MWO) © 2011 42
  • 43.
    S-functions Verification –Constantness of LSOP Select LSOP variable Variation on Filter for a LSOP variable drain bias voltage and value Variation on fixed input power © 2011 43
  • 44.
    S-functions Verification –Interpolation Capability verify interpolation of b2 using independent set of measurements © 2011 44
  • 45.
    S-functions Verification –Linearity Assumption of Tickle Tones Large-Signal DC Bias f0 f0 or Large-Signal Tickling Source k f0 ZL Source Small-Signal for harmonics DC Bias DC Bias a 2 k f 0 Switching Amplifier design  L 2 f 0   L  k f 0  L 3 f 0 a 2 2 f 0  Still small signal? a 2 3 f 0 © 2011 45
  • 46.
    ICEBreaker – OptionS-function Verification Tool ICEBreaker Predicted Compare Dataset ICEBreaker Datasets Dataset ● Measured Data ● Using S-function ● Derived Quantities ● Realistic Sweep Plan ● Incident / Reflected Waves ● Under multi-harmonic Load-Pull ● Voltage and Current ● Absolute Error ● Relative Error © 2011 46
  • 47.
    Generation of “S-functionPredicted Dataset” in ICEBreaker Generate S-function based Dataset Compare Dataset and S-function based Dataset © 2011 47
  • 48.
    Absolute Comparisons withS-function Predictions Quantity for which to compare measurement and Idc_out prediction ● Derived quantities ➢ Idc_out ➢ Gain ➢ Pdel_in ➢ Pdel_out ➢ PAE ➢ .. ➢ Frequency selection ● Basic quantities ➢ Incident waves ➢ Reflected waves ➢ Voltages / Currents ➢ Frequency selection Measurements S-function Prediction Absolute Error © 2011 48
  • 49.
    Relative Comparisons withS-function Predictions b_out(3f0) ● Versus ➢ Harmonic index ➢ Harmonic refl Relative Error (dB) © 2011 49
  • 50.
    Case Study(*): EPA120B-100P  EPA120B-100P • high efficiency heterojunction power FET • power output: + 29.0dBm typ. • power gain: 11.5dB typ. @ 12 GHz Real Device Virtual Device (*) : all results in this slide set are based on S-function extraction and deployment for this device © 2011 © 2009 - NMDG NV 50
  • 51.
    Data Collection withZVxPlus LSOP “tickle” sweep settings detailed detailed feedback feedback of LSOP on tickle for actual for actual measurement measurement © 2011 51
  • 52.
    Expert Details IfDesired @ Data Collection Summary Monitor RF and DC source settings Observe what happens at the DUT © 2011 52
  • 53.
    S-functions Extraction S11 S12 S22 S21 meaningful complex ~3 dB compression conjugate © 2011 53
  • 54.
    S-functions Verifications –Residual Error zoom in on zoom in tickling on result Number of measurements required to extract S-functions amplitude of complex error for measured and predicted b2 using extraction data © 2011 54
  • 55.
    S-functions Verification –Interpolation Capability verify interpolation of b2 using independent set of measurements © 2011 55
  • 56.
    S-functions Verifications –Constantness LSOP Select LSOP variable Variation on Filter for a LSOP variable drain bias voltage and value Variation on fixed input power © 2011 56
  • 57.
    S-functions in ADS Acknowledgement: Withthe support from Agilent Technologies providing ADS licensing © 2011 57
  • 58.
    S-functions Useage inAgilent ADS EPAClassAMediumPower.ael EPAClassAMediumPower.dsn Set of equations using FDD Values of all Sf, Sfc © 2011 58
  • 59.
    S-functions Verification inADS - Schematic ● Example: Harmonic Balance simulation with measured a1 and a2 spectra ● Excitation: Sweeping through a subset of LSOP points + tickle tones Measured incident waves S-function to be verified Measurements for model verification Access to measured data using DAC Sweeping through subset of LSOP and tickle tones © 2011 59
  • 60.
    S-functions Verification inADS - Frequency Domain Frequency = 2 GHz, VDC1= -1.3 V, VDC2= +2.0 V Measurements at different input powers than those which were used for S-functions model extraction! circles – measurements solid lines - simulations © 2011 60
  • 61.
    S-functions Verification inADS - Time Domain circles – measurements Frequency = 2 GHz, VDC1= -1.3 V, VDC2= +2.0 V, Pa1 = +10.0 dBm solid lines - simulations Saturation Pinch-off © 2011 61
  • 62.
    S-functions in ADS– Modulation Prediction - Schematic Frequency = 2 GHz, VDC1= -1.37 V, VDC2= +4.0 V, Pa1 = +0.0 dBm – Class C © 2011 62
  • 63.
    S-functions in ADS– Modulation Prediction - Display Frequency = 2 GHz, VDC1= -1.37 V, VDC2= +4.0 V, Pa1 = +0.0 dBm – Class C © 2011 63
  • 64.
    S-functions in ADS– Source-Pull - Schematic Frequency = 2 GHz, VDC1= -1.37 V, VDC2= +4.0 V, Pav = +1.0 dBm – Class C Reflection : -0.27 © 2011 64
  • 65.
    S-functions in ADS– Source-Pull - Schematic Frequency = 2 GHz, VDC1= -1.37 V, VDC2= +4.0 V, Pav = +1.0 dBm – Class C Complex Conjugate Measured Input Impedance © 2011 65
  • 66.
    S-functions in MWO Acknowledgement: Withthe support from AWR providing MWO / VSS licensing © 2011 66
  • 67.
    S-functions Usage inAWR MWO MDF file SUBCKT ID=S1 BIASTEE NET="SFUNC_Model" ID=X2 1 RF 2 & RF BIASTEE 2 DC DC ID=X1 PORT 3 P=2 Z=50 Ohm Model data 2 RF 1 1 RF & DC DC PORT_PS1 3 DCVS .. P=1 Z=50 Ohm ID=V2 .. V=6 V PStart=PinMin dBm 1.16226472890446E-16,-1.35308431126191E-16 PStop=PinMax dBm PStep=PinStep dB -3.15025783237388E-15,4.72191730160887E-15 DCVS ID=V1 9.71445146547012E-17,-2.37310171513627E-15 V=-1.8 V 1.51267887105178E-15,1.07899800205757E-15 -2.98198965520413E-15,1.59594559789866E-15 -5.759281940243E-16,-1.97758476261356E-16 -1.83880688453542E-15,1.92901250528621E-15 -5.06539254985228E-16,2.94209101525666E-15 -2.50494069931051E-15,-6.73072708679001E-16 -8.60422844084496E-16,2.65412691824451E-16 -2.019218126037E-15,2.7373936450914E-15 -2.28289609438548E-15,1.70870262383715E-15 1.08246744900953E-15,-6.78276879106932E-16 -1.02955838299224E-15,-1.31578775652841E-15 5.45570533194706E-16,3.99333344169861E-15 -3.62904151174348E-15,-1.74860126378462E-15 -2.00100352953925E-15,-5.68989300120393E-16 2.14975606760426E-15,-5.53376788836601E-16 -1.16226472890446E-15,-2.44942954807925E-15 2.08166817117217E-16,2.4980018054066E-15 1.04372118124342E-05,-1.36061371223614E-05 2.85882428840978E-15,3.11556336285435E-15 -2.15105711021124E-16,1.37390099297363E-15 9.71445146547012E-16,9.95731275210687E-16 -1.69309011255336E-15,2.33146835171283E-15 4.27435864480685E-15,3.3584246494911E-15 -1.08246744900953E-15,-8.60422844084496E-16 … 2D and 3D package data © 2011 67
  • 68.
    S-functions Verification inMWO - Frequency Domain HBT UNER2 ID=X1 Mag1=0 Ang1=0 Deg Mag2=0 Ang2=0 Deg Mag3=0 Ang3=0 Deg Fo=2 GHz Zo=50 Ohm PORT _PS1 P=1 1 2 Z=50 Ohm PStart=-20 dBm BIAST EE 2 PStop=8 dBm ID=X2 PORT PStep=1 dB 3:Bias P=2 SUBCK T 2 RF 1 1 Z=50 Ohm RF & ID=S1 DC NET ="EPA_120_B " DC 3 DCVS ID=V1 V=DC2val V DCVS ID=V2 V=DC 1val V Po with swept Pin Gain and Phase with swept Pin 40 20 19.5 20 19 F0 18.5 DB(|LSSnm(PORT_2,PORT_1,1,1)|)[1,X] 0 18 Swept Power.AP_HB Ang(LSSnm(PORT_2,PORT_1,2,1))[1,X] (Deg) 17.5 Swept Power.AP_HB -20 17 150 2F0 -40 100 DB(|Pcomp(PORT_2,1)|)[1,X] (dBm) Swept Power.AP_HB 50 3F0 DB(|Pcomp(PORT_2,2)|)[1,X] (dBm) -60 Swept Power.AP_HB DB(|Pcomp(PORT_2,3)|)[1,X] (dBm) Swept Power.AP_HB 0 -80 -50 -20 -15 -10 -5 0 5 10 -20 -15 -10 -5 0 5 10 Power (dBm) Power (dBm) © 2011 68
  • 69.
    S-functions Verification inMWO - Time Domain Vtime(V_METER.VM1,1)[*,T] (V) Itime(I_METER.AMP1,1)[*,T] (mA) HBTUNER2 Waveform Tests.AP_HB Waveform Tests.AP_HB ID=X1 Mag1=0 Ang1=0 Deg Mag2=0 Ang2=0 Deg Mag3=0 IV Ang3=0 Deg 250 Fo=2 GHz SUBCKT Zo=50 Ohm PORT_PS1 ID=S1 200 P=1 NET="EPA_120_B" 1 2 Z=50 Ohm PStart=-20 dBm BIASTEE 2 150 PStop=8 dBm ID=X2 PORT PStep=1 dB I_METER 3:Bias P=2 2 RF 1 1 ID=AMP1 Z=50 Ohm 100 RF & DC DC 50 3 V _METER DCVS ID =VM1 ID=V1 V=DC2val V 0 15 DCVS ID=V2 V=DC1val V 10 5 DB(|Pcomp(PORT_2,1)|)[1,X] (dBm) DB(|Pcomp(PORT_2,2)| )[1,X] (dBm) DB(|Pcomp(PORT_2,3)|)[1,X] (dBm) Waveform Tests.AP_HB Waveform Tests.AP_HB Waveform Tests.AP_HB0 0 0.2 0.4 0.6 0.8 1 Harmonics 40 Time (ns) 20 0 -20 -40 -60 -80 -20 -10 0 8 Power (dBm) © 2011 69
  • 70.
    S-functions in MWO– Modulation Prediction - Schematic DB(PWR_SPEC(TP.AMP Out,1000,0,10,0,-1,0,-1,1,0,4,0,1,0)) (dBm) DB(PWR_SPEC(TP.AMP In,1000,0,10,0,-1,0,-1,1,0,4,0,1,0)) (dBm) 16QAM System 16QAM System HBTUNER2 ID=DCBlock2 Mag1=0 Ang1=0 Deg Mag2=0 Ang2=0 Deg Mag3=0 ACPR SUBCKT Ang3=0 Deg Fo=2000 GHz 50 ID=S1 Zo=50 Ohm ISOL8R NET="EPA_120_B" ID=U1 1 2 R=50 Ohm LOSS=0 dB BIASTEE 2 ISOL=30 dB ID=X1 PORT 3:Bias P=2 2 RF RF & 1 1 Z=50 Ohm 0 DC DC PORT_PS1 3 DCVS P=1 ID=V3 Z=50 Ohm V=DC2val V PStart=-20 dBm PStop=8 dBm PStep=0.5 dB DCVS -50 ID=V1 V=DC1val V -100 -150 1.92 1.94 1.96 1.98 2 2.02 2.04 2.06 2.08 Frequency (GHz) VS A ID=M1 VA RNA ME="" VA LUE S=0 NA VG= PBA SE = -76 V e c to r S w e p t v a r ia b le S ig n a l SRC MEAS A n a ly z e r QAM_S RC G e n e r a l R e c e iv e r ID=A1 MO D=16-QA M (Gray) OUT LV L=-0.2 OLVLT Y P=Avg. Power (dB m) NL_ S AW GN RAT E=_DRA T E ID=S 1 BER ID=A3 CTRFRQ=2 GHz TP NET ="AMAM A MPM.AP_HB " PW R=-170 ID=5 SIMT YP=Harm onic Balanc e TP PLST Y P=Root Rais ed Cos ine ID=AMP In PW RT YP=Avg. Po wer, Sym bol (dBW ) VARNAME="PBA SE" ID=AMP Out ALPHA =0.35 NO SE=RF Budget only I VALUES=s tepped(-76,-40,2) LOSS=0 dB PLSLN= RFIF RQ= QAM_RX OUT FL="" ID=A 2 1 R D 2 BER IQ 3 C irc u it 5 4 B E R D e te c to r B a s e d A m p lifie r C h a n n e l N o is e 1 6 Q A M S o u rc e TP ID=RX Cons tellation 1 6 Q A M (G r a y ) S y s te m © 2011 70
  • 71.
    S-functions in MWO– Load-Pull HBTUNER2 ID=DCBlock2 Mag1=0.8 Load Tuner (and bias) Ang1=40 Deg LP_Data_Low_Power Mag2=0 Ang2=0 Deg 1.0 Swp Max Mag3=0 0.8 -0.89 Ang3=0 Deg Fo=2 GHz 6 0. Zo=50 Ohm 0 . 2 4 . 1 2 PORT1 0 0 . 3 P=1 2 p8 0 p1: Pcomp_PORT_2_1_M_DB = -2.87 Z=50 Ohm PORT p7 4. Pwr=10 dBm 3:Bias P=2 p9 p2: Pcomp_PORT_2_1_M_DB = -2.65 SUBCKT 5. 0 2 RF 1 Z=50 Ohm 2 p6 1 ID=S1 0. RF & p10 p3: Pcomp_PORT_2_1_M_DB = -2.43 DC NET="SFUNC_Model" p5 DC 10. 0 BIASTEE p4: Pcomp_PORT_2_1_M_DB = -2.21 3 DCVS ID=X1 p4 ID=V2 10.0 V=7 V 4.0 p5: Pcomp_PORT_2_1_M_DB = -1.99 0.2 0.4 0.6 0.8 1.0 2.0 3.0 5.0 0 p3 p6: Pcomp_PORT_2_1_M_DB = -1.77 DCVS p2 ID=V1 .0 -10 p7: Pcomp_PORT_2_1_M_DB = -1.55 V=-0.6 V p1 -0 . 2 0 . p8: Pcomp_PORT_2_1_M_DB = -1.33 -5 0 . -4 p9: Pcomp_PORT_2_1_M_DB = -1.11 p10: Pcomp_PORT_2_1_M_DB = -0.89 0 . 3 4 - . 0 - 0 . 2 6 - . -0 8 Swp Min -1.0 -0. -2.87 LP_Data_High_Power S M wp ax 1.0 0 .8 25.93 6 0. .0 2 .4 0 p1: Pcomp_PORT _2_1_M_DB = 21.93 .0 3 p9 p8 p7 p6 p5 p2: Pcomp_PORT _2_1_M_DB = 22.33 p4 4 .0 2 p10 p3 5. 0 p3: Pcomp_PORT _2_1_M_DB = 22.73 0. p2 0 p4: Pcomp_PORT _2_1_M_DB = 23.13 1 0. p11 p5: Pcomp_PORT _2_1_M_DB = 23.53 10.0 0.4 0.8 3.0 0.2 0.6 1.0 2.0 4.0 5.0 p1 p6: Pcomp_PORT _2_1_M_DB = 23.93 0 0 . p7: Pcomp_PORT _2_1_M_DB = 24.33 - 10 p8: Pcomp_PORT _2_1_M_DB = 24.73 .2 -0 .0 .0 -5 p9: Pcomp_PORT _2_1_M_DB = 25.13 -4 0 p10: Pcomp_PORT _2_1_M_DB = 25.53 3. 4 - 0. - p11: Pcomp_PORT _2_1_M_DB = 25.93 0 2. .6 - -0 8 S M wp in -1.0 - 0. 21.93 © 2011 71
  • 72.
    S-functions Strengths ● S-functions are completely public ● S-functions are transparent ● S-functions are connected into ADS and MWO and can be connected in other tools on request, e.g. Matlab ● S-functions are closely integrated with load-pull in general and especially with tuners from Focus Microwave ● S-functions extraction tool has a verification capability for LSOP constantness and interpolation capability, investigating quality of model, without needing a simulation tool ● The source- and load-pull software ICEBreaker from NMDG allows S- function verification, related to the linearity assumption ● Customers can explore the capabilities of S-functions via NMDG services © 2011 72
  • 73.
    S-Functions - KeyCapabilities ● Natural extension of S-parameters ● Reduce to S-parameters for small-signal excitation ● S-parameters are cascadeable, S-Functions are cascadeable too ● e.g. Transistors, amplifiers, dividers, multipliers ● Predict harmonic behaviour of components under different impedances ● Source – Pull ● Load – Pull ● Harmonic distortion, Waveforms ● Predict modulation behaviour of components under different impedances ● When no long-term memory effects ● Valid for multi-ports, applicable to differential components © 2011 73
  • 74.
    References ● F. Verbeyst and M. Vanden Bossche, “VIOMAP, the S-parameter equivalent for weakly nonlinear RF and microwave devices”, published in the Microwave Symposium Digest of IEEE 1994 MTT-S International and published in the 1994 Special Symposium Issue of the MTT Transactions, vol. 42, no. 12, pp. 2531 – 2535. ● F. Verbeyst and M. Vanden Bossche, “VIOMAP, 16QAM and Spectral Regrowth: Enhanced Prediction and Predistortion based on Two-Tone Black-Box Model Extraction”, published in the Proceedings of the 45th ARFTG Conference, Orlando, June 1995 and winner of the “Best Conference Paper Award”. ● J. Verspecht and P. Van Esch, “Accurately characterizating of hard nonlinear behaviour of microwave components by the Nonlinear Network Measurement System: introducing the nonlinear scattering function,” Proc. International Workshop on Integrated Nonlinear Microwave and Millimiterwave Circuits (INMMiC), October 1998, pp.17-26. ● J. Verspecht, “Scattering functions for nonlinear behavioral modeling in the frequency domain,” IEEE MTT-S Int. Microwave Symp. Workshop, June 2003. ● J. Verspecht and D.E. Root “Polyharmonic Distortion Modeling,” IEEE Microwave Magazine, vol.7 no.3, June 2006, pp.44-57. ● D.E. Root, J. Horn, L. Betts, C. Gillease, and J. Verspecht, ”X-Parameters: The new paradigm for measurement, modeling, and design of nonlinear RF and microwave components,” Microwave Engineering Europe, December 2008, pp. 16-21. © 2011 74
  • 75.
    Conclusion ● S-functions are a natural extension to S-parameters for nonlinear behaviour ● S-functions aren't much more complex than S-parameters ● S-functions are accurate when assumptions are not violated ● Linearity assumption ● S-function extraction is supported on R&S network analysers ● S-functions can be coupled into ADS and MWO ● S-functions can be used to compress or hide specifics of nonlinear circuits in ADS and MWO For more information info@nmdg.be www.nmdg.be © 2011 75
  • 76.
    Explore the powerof S-functions Send your device or circuit to NMDG ... ` … and NMDG sends you the S-functions Please contact NMDG at info@nmdg.be © 2011 76