This document describes ICEBreaker, a tool for verifying S-parameter models of nonlinear devices against measured data. It discusses potential issues with S-parameter models like changes in operating point, interpolation errors, and the assumption of linearity. ICEBreaker addresses these by comparing S-parameter predicted data to complex multi-tone measured datasets, identifying errors in quantities like power, efficiency, and waves. The tool allows engineers to verify S-functions under realistic conditions to have confidence in their accuracy.

1. ICEBreaker
Option S-function Verification Tool
- Using your VNA at its full power -
Sept 2010

2. Outline
● From S-parameters to S-functions
● Potential Pitfalls
● Confidence in S-functions through verification
● ICEBreaker – Option S-function Verification Tool
● Measured datasets
● Datasets, predicted by S-functions
● Comparison tools
● Conclusion
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3. From S-parameters to S-functions
?
Linear Applications
All
S-parameters Other
NonLinear
? Applications
?
“NonLinear” Applications
S-functions
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4. The Potential Pitfalls
“Tickle tones”
Large-Signal Operating Point
Bi  j =Sf ijx1a 1  f 0 , a2  f 0  , v dc Sf ijkl a 1  f 0 , a 2  f 0  , v dc  Ak l f 0 
*
Sfc ijkl a 1  f 0 , a 2  f 0  , v dc  Ak l f 0 
● Constantness of LSOP ● Linearity Assumption
● Interpolation Capability
ICEBreaker
Option S-function Verification Tool
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5. Confidence in S-functions through Verification
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6. Pitfall 1: Constantness of LSOP
Part of S-function Visualization
Select LSOP variable
Variation on
drain bias voltage
Filter for a LSOP variable
and value
Variation on fixed input power
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7. Pitfall 2: Interpolation Capability
Part of S-function Extraction Visualization
zoom in
on zoom in
tickling on result
amplitude of complex error for measured and predicted b2
Number of measurements
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8. Pitfall 3: Linearity Assumption
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
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9. 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
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10. Generation of “S-function Predicted Dataset” in ICEBreaker
Generate
S-function based
Dataset
Compare
Dataset
and
S-function based
Dataset
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11. 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
➢ ..
● Basic quantities
➢ Incident waves
➢ Reflected waves
➢ Voltages / Currents
● Style
➢ Points
➢ Contours
➢ Points & Contours
Measurements
S-function
Prediction
Absolute Error
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12. Relative Comparisons with S-function Predictions
b_out(3f0)
● Versus
➢ Harmonic index
➢ Harmonic refl
● Desired
● Realized
Relative Error (dB)
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13. Conclusion
Using the complex multi-harmonic sweep plans of
ICEBreaker it is easy to verify the S-functions under a
series of realistic conditions
- Use your VNA at its full power -
For more information info@nmdg.be
www.nmdg.be
© NMDG 2010 13

14. Want to try?
Contact us
at
icesupport@nmdg.be
© NMDG 2010 14