LNA.ppt

Microwave Office 2005 Training
Linear Simulation – Low Noise Amplifier

Section 5 Page 2
AWR, Inc. Company Confidential
Linear Simulation
• The design of a Low Noise Amplifier (Hands-on work)
• Creating schematics
• Data libraries
• Editing schematic symbols (adding explicit ground nodes)
• Creating graphs
• Adding measurements to the graphs
• Advanced measurements
• Tuning as a design aid

Section 5 Page 3
• Design Goals for a 5GHz amplifier:
– Gain : > 10 dB
– NF: < 1.2 dB
– Stability: Unconditional at all frequencies
• Create schematic and name the schematic ‘Device’
• Select Device suitable for design from the device library. Use the Fujitsu
FHX35LG data set. This will import the S-Parameter and Noise data for
the device.
• Add simple schematic, graphs and measurements
• Add the port parameters S11 and S22, gain parameters S21 and MSG
• Add the stability parameters K and B1, noise parameters NF and NFmin
The Design of a Low Noise Amplifier
(Hands on work)

Section 5 Page 4
(Hands on work)
• Place FHX35LG HEMT into schematic
– Alternatively, you can import the data file from the project
view (Right click Data Files, select “Import Data Files”)
1 2
SUBCKT
NET=
ID=
"FHX35LG"
S1
NOTE: When a data file has been
read into a project it will be visible
in the project tree.
HINT: The HEMT will be found in
the data library, use the element tree
and browse to Fujitsu parts.

Section 5 Page 5
• Edit the symbol to use an explicit ground node
1 2
3
SUBCKT
NET=
ID=
"FHX35LG"
S1
NOTE: Double click a schematic
symbol to open the Element Options
dialog box.
(Hands on work)

Section 5 Page 6
• Change the symbol to a FET symbol
NOTE: Only symbols with three
nodes will be listed.
(Hands on work)

Section 5 Page 7
• Add two ports and connect these to the transistor
HINT: Use the right mouse button to
rotate the PORT symbol before
placement into schematic.
(Hands on work)

Section 5 Page 8
• Set Project frequencies 0.1GHz to 20GHz Step 0.1GHz
– From the Project Tree double click ‘Project Options’
HINT: CLICK the Apply button to
set the frequencies before closing the
Project Options dialogue box.
(Hands on work)

Section 5 Page 9
• Examine the data set belonging to the transistor
• Right click the transistor symbol, and select “Edit Subcircuit”
• Examine the data, linear S-Parameters and Noise data
NOTE: A window containing the S-Data will open.
NOTE: It is possible to edit this data. BEWARE!
(Hands on work)

Section 5 Page 10
• Create a graph called Input Port, add a measurement for S11
– (measurement type = Port Parameters)
• Create a graph called Output Port, add a measurement for S22
– (measurement type = Port Parameters)
0
1.0
1.0
-1.0
10.0
10.0
-
1
0
.
0
5.0
5.0
-
5
.
0
2.0
2
.
0
-
2
.
0
3.0
3.0
-
3
.
0
4.0
4.0
-
4
.
0
0.2
0
.
2
-0.2
0.4
0
.
4
-0.4
0.6
0
.
6
-
0
.
6
0.8
0
.
8
-
0
.
8
Outport Port
Swp Max
20GHz
Swp Min
0.1GHz
S[2,2]
Device
0
1.0
1.0
-1.0
10.0
10.0
-
1
0
.
0
5.0
5.0
-
5
.
0
2.0
2
.
0
-
2
.
0
3.0
3.0
-
3
.
0
4.0
4.0
-
4
.
0
0.2
0
.
2
-0.2
0.4
0
.
4
-0.4
0.6
0
.
6
-
0
.
6
0.8
0
.
8
-
0
.
8
Input Port
Swp Max
20GHz
Swp Min
0.1GHz
S[1,1]
Device
Note: You might get the warning message that the noise data has problems at 20 GHz.
This is because the noise data only goes to 18 GHz. If you do, proceed anyway – the
software extrapolates the noise data.
(Hands on work)

Section 5 Page 11
0 5 10 15 20
Frequency (GHz)
Two Port Gain
0
10
20
30
40
DB(|S[2,1]|)
Device
DB(MSG)
Device
• Create a graph called Two Port Gain, add measurements for S21 (measurement type = Port
Parameters) and MSG (measurement type = Linear Gain)
• Double click the trace definition to open the Graph Properties dialog box
• Uncheck the Auto limits box, and set the minimum frequency to 0
(Hands on work)

Section 5 Page 12
• Create a graph called Two Port Noise Parameters, add measurements for NF and NFmin
– (measurement type = Noise)
• Double click the trace definition to open the Graph Properties dialog box
• Uncheck the Auto limits box, and set the minimum frequency to 0
0 5 10 15 20
Frequency (GHz)
Two Port Noise Parameters
0
0.5
1
1.5
2
2.5
3
DB(NF)
Device
DB(NFMin)
Device
(Hands on work)

Section 5 Page 13
• Create a graph called ‘Stability Data’, add measurements for K and B1
– (measurement type = linear)
• Add a marker to the K factor plot and search for the K value “1”
• Save the project and then Quit MWO
0 5 10 15 20
Frequency (GHz)
Stability Data
0
0.5
1
1.5
11.763 GHz
1
B1
Device
K
Device
NOTE: Do not select dB for K and B1
NOTE: Select the
legend box, Right
click, choose
‘Search’
(Hands on work)

Section 5 Page 14
• Start MWO and load the previous project
• Add the extra components shown below
• Rename schematic ‘Stable Device’
HINT: Drag the first resistor from the
element browser, then copy and paste
the second and third resistors.
(Hands on work)

Section 5 Page 16
• Examine the changes in ‘amplifier gain block performance’
– For example the the S21 and the port parameters S11,S22
0
1.0
1.0
-1.0
10.0
10.0
-
1
0
.
0
5.0
5.0
-
5
.
0
2.0
2
.
0
-
2
.
0
3.0
3.0
-
3
.
0
4.0
4.0
-
4
.
0
0.2
0
.
2
-0.2
0.4
0
.
4
-0.4
0.6
0
.
6
-
0
.
6
0.8
0
.
8
-
0
.
8
Input Port
Swp Max
20GHz
Swp Min
0.1GHz
S[1,1]
Stable Device
(Hands on work)

Section 5 Page 17
Operating Point
0 5 10 15 20
Frequency (GHz)
Two Port Noise Parameters
0
1
2
3
4
5
6
7
8
9
10
DB(NF)
Stable Device
DB(NFMin)
Stable Device
• Examine the changes in ‘amplifier gain block performance’
– Note that K and B1 are consistent with a wideband stable device
0 5 10 15 20
Frequency (GHz)
Stability Data
-1
0
1
2
3
4
5
6
7
8
9
B1
Stable Device
K
Stable Device
(Hands on work)

Section 5 Page 18
HINT: Reset the project frequency
range to a few frequencies to reduce
the amount of data visible.
• With the project frequencies unchanged add NF circles and Stability circles.
– (measurement type = Circle)
(To get to this point load Linear Simulation_p17.emp if required)
(Hands on work)

Section 5 Page 19
• Set project frequency to 5GHz
• Create a new schematic named “Input Matching Circuit” as shown
• Create a new schematic named “Amp” using the subcircuits
1 2
SUBCKT
ID=S1
NET="Input Matching Circuit"
1 2
SUBCKT
ID=S2
NET="Stable Device"
PORT
P=1
Z=50 Ohm
PORT
P=2
Z=50 Ohm
IND
ID=L1
L=2 nH
IND
ID=L2
L=2.77 nH
PORT
P=1
Z=50 Ohm
PORT
P=2
Z=50 Ohm
RES
ID=R1
R=300 Ohm
TLIN
ID=TL1
Z0=75.4 Ohm
EL=90 Deg
F0=5 GHz
RES
ID=R2
R=450 Ohm
RES
ID=R3
R=20 Ohm
1
2
3
SUBCKT
ID=S1
NET="FHX35LG"
PORT
P=1
Z=50 Ohm
PORT
P=2
Z=50 Ohm
(Hands on work)

Section 5 Page 20
Details of Input Matching Circuit

Section 5 Page 21
• Activate “L” for tuning and limit the tuning ranges of both L1 and L2 from 0 – 10 nH as
shown below
HINT: The Min and Max
range of the tuner will be set
by these element properties.
(Hands on work)

Section 5 Page 22
0
1.0
1.0
-1.0
10.0
10.0
-
1
0
.
0
5.0
5.0
-
5
.
0
2.0
2
.
0
-
2
.
0
3.0
3.0
-
3
.
0
4.0
4.0
-
4
.
0
0.2
0
.
2
-0.2
0.4
0
.
4
-0.4
0.6
0
.
6
-
0
.
6
0.8
0
.
8
-
0
.
8
Input Port Of Device
Swp Max
5GHz
Swp Min
5GHz
NFCIR[2,0.5]
Stable Device
GAC_MAX[1,2]
Stable Device
S[2,2]
Input Matching Circuit
• Change the Input Smith Chart to show “Amp” parameters and tune the
inductors to obtain a compromise between Gain and NF
Noise Circles.
Gain Circles.
(Hands on work)

Section 5 Page 23
• Add a simple output matching circuit, maximize the gain of the amplifier
and use the tuner to adjust circuit values
1 2
SUBCKT
ID=S1
NET="Input Matching Circuit"
1 2
SUBCKT
ID=S2
NET="Stable Device"
1 2
SUBCKT
ID=S3
NET="Output Matching Circuit"
PORT
P=1
Z=50 Ohm
PORT
P=2
Z=50 Ohm
IND
ID=L1
L=2.18 nH
CAP
ID=C1
C=100 pF
PORT
P=1
Z=50 Ohm
PORT
P=2
Z=50 Ohm
(Hands on work)

Section 5 Page 24
0 5 10 15 20
Frequency (GHz)
Gain And Match
-40
-30
-20
-10
0
10
20 DB(|S[2,1]|)
Amplifier
DB(|S[1,1]|)
Amplifier
DB(|S[2,2]|)
Amplifier
0 5 10 15 20
Frequency (GHz)
Noise
0
1
2
3
4
5
6
7
8
9
10
DB(NF)
Amplifier
• Reset the project frequency plan to the original wideband set
• Save project, giving it a suitable name, and quit MWO
(Hands on work)

Section 5 Page 25
TXLine Calculator
• Under the Tools menu…TXLine….
– We can predict the practical equivalent line dimensions
RES
R=
ID=
325 Ohm
R1
TLIN
F0=
EL=
Z0=
ID=
5 GHz
90 Deg
75.4 Ohm
TL1
PORT
Z=
P=
50 Ohm
1

Section 5 Page 26
• Run MWO
• Create two new schematics (ideal and physical)
RES
ID=R1
R=300 Ohm
TLIN
ID=TL1
Z0=75.4 Ohm
EL=90 Deg
F0=5 GHz
PORT
P=1
Z=50 Ohm
RES
ID=R1
R=300 Ohm
MLIN
ID=TL1
W=31.41 mil
L=431.7 mil
VIA
ID=V1
D=20 mil
H=20 mil
T=1.4 mil
RHO=1
MSUB
Er=2.2
H=20 mil
T=1.4 mil
Rho=1
Tand=0.0009
ErNom=2.2
Name=SUB1
PORT
P=1
Z=50 Ohm
(Hands on work)

Section 5 Page 27
• Create a graph called ‘Both’ and add S11 measurements from both schematics
• Tune length of MLIN until they have similar performance
0.1 5.1 10.1 15.1 20
Frequency (GHz)
Both
-3
-2
-1
0
DB(|S[1,1]|)
Ideal
DB(|S[1,1]|)
Physical Shunt Circuit
(Hands on work)

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