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.amp file definition leading warning on impedance

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Changlin Chen
Changlin Chen on 12 Sep 2013
I create the following .AMP file called by 'General Amplifier' in SimRF.
I did not have the S-parameter of the amp, only the Pin, Pout and Phase info as attached below. I keep getting the warning message:
Warning: Reference Impedance invalid, the default value: 50 ohms is used.
I have tried to R 50 into the file, but the warning message did not disappear. Does the impedance always go with the S-parameter data?
Question 1: How to get the impedance properly defined in the amp file and fix the warning?
Question 2: If have multiple freq data for Pin, Pout and Phase, is it correct to concatenate Pin Pout and Phase one frequency after another?
------------------- below is the amp file defined
* the data of a 10.7GHz amplifier in .AMP format of the MathWorks
S RI R 50
FREQ GHz
* FREQ reS11 imS11 reS21 imS21 reS12 imS12 reS22 imS22
POUT dBm
PIN dBm FREQ = 10.7 GHz
* Pin Pout Phase(degrees)
-7 6.2 0
-6.91 6.29 0
-6.79 6.42 0.0277
-6.65 6.55 0.04
-6.53 6.68 0.0657
-6.39 6.81 0.1008
-6.26 6.93 0.1308
-6.13 7.07 0.1538
-6 7.2 0.1664
-5.87 7.33 0.1762
-5.74 7.46 0.1862
-5.61 7.59 0.2071
-5.47 7.72 0.2508
-5.33 7.86 0.3046
-5.21 7.99 0.3385
-5.08 8.11 0.35
-4.95 8.25 0.36
-4.82 8.37 0.3885
-4.69 8.51 0.4146
-4.56 8.63 0.4292
-4.43 8.77 0.4585
-4.3 8.89 0.5031
-4.17 9.03 0.5386
-4.05 9.15 0.5531
-3.91 9.28 0.5671
-3.78 9.42 0.5954
-3.65 9.55 0.6357
-3.51 9.68 0.6592
-3.38 9.81 0.6954
-3.26 9.94 0.7369
-3.13 10.07 0.7686
-2.99 10.2 0.8023
-2.87 10.33 0.8177
-2.74 10.46 0.8643
-2.61 10.58 0.8931
-2.47 10.71 0.9362
-2.35 10.84 0.9708
-2.22 10.97 0.9829
-2.08 11.1 1.0223
-1.95 11.24 1.0529
-1.82 11.37 1.09
-1.69 11.5 1.12
-1.56 11.63 1.15
-1.43 11.75 1.19
-1.3 11.89 1.24
-1.17 12.01 1.28
-1.04 12.15 1.345
-0.92 12.27 1.3838
-0.79 12.41 1.4238
-0.66 12.53 1.4723
-0.53 12.66 1.5138
-0.39 12.8 1.5477
-0.26 12.93 1.5929
-0.13 13.06 1.6508
-0.01 13.19 1.7062
0.13 13.32 1.7538
0.25 13.44 1.7957
0.39 13.58 1.8671
0.52 13.7 1.9246
0.65 13.84 1.9815
0.77 13.96 2.0185
0.9 14.1 2.0546
1.04 14.23 2.0977
1.17 14.36 2.1446
1.3 14.49 2.1986
1.43 14.61 2.2692
1.56 14.75 2.3431
1.69 14.87 2.4131
1.82 15.01 2.4743
1.94 15.13 2.5323
2.07 15.27 2.6069
2.2 15.39 2.6869
2.33 15.53 2.76
2.45 15.65 2.8246
2.59 15.79 2.9108
2.72 15.92 2.9908
2.85 16.06 3.0631
2.99 16.19 3.1323
3.11 16.32 3.2021
3.24 16.45 3.2877
3.37 16.58 3.3746
3.5 16.71 3.4515
3.62 16.84 3.5185
3.76 16.97 3.6029
3.88 17.1 3.6723
4.01 17.23 3.7538
4.14 17.36 3.8408
4.27 17.49 3.9123
4.4 17.63 3.9914
4.53 17.76 4.0658
4.66 17.9 4.1386
4.79 18.02 4.1938
4.92 18.15 4.2454
5.05 18.28 4.3154
5.18 18.41 4.385
5.3 18.54 4.445
5.44 18.67 4.53
5.56 18.8 4.5854
5.69 18.93 4.6362
5.82 19.06 4.6862
5.95 19.19 4.7454
6.08 19.31 4.7843
6.21 19.44 4.8323
6.35 19.57 4.8769
6.47 19.7 4.9054
6.6 19.82 4.9269
6.72 19.94 4.9514
6.86 20.07 4.96
6.98 20.19 4.9669
7.12 20.31 4.97
7.24 20.43 4.97
7.37 20.55 4.9492
7.5 20.67 4.9192
7.63 20.78 4.8843
7.76 20.9 4.8454
7.89 21 4.7931
8.02 21.12 4.7269
8.15 21.22 4.6508
8.28 21.32 4.5686
8.41 21.42 4.4815
8.54 21.52 4.3808
8.66 21.61 4.27
8.79 21.71 4.1354
8.92 21.8 4
9.05 21.89 3.8623
9.19 21.97 3.6962
9.32 22.05 3.5315
9.45 22.13 3.3569
9.57 22.2 3.1946
9.7 22.27 3.0257
9.83 22.33 2.8515
9.96 22.4 2.6585
10.09 22.45 2.4615
10.22 22.51 2.2715
10.34 22.56 2.1008
10.47 22.61 1.9262
10.6 22.65 1.7393
10.73 22.7 1.5608
10.86 22.74 1.3723
10.99 22.77 1.1938
11.13 22.81 1.0108
11.25 22.83 0.8538
11.38 22.86 0.6869
11.51 22.89 0.5386
11.63 22.91 0.41
11.76 22.93 0.29
11.89 22.94 0.16
12.02 22.96 0.05
12.15 22.97 -0.05
12.28 22.98 -0.1243
12.41 22.98 -0.1854
12.54 22.99 -0.2454
12.67 22.99 -0.2869
12.8 23 -0.3085
12.93 23 -0.31
13.06 22.99 -0.3014
13.19 22.99 -0.2662
13.32 22.99 -0.2177
13.45 22.98 -0.1508
13.58 22.98 -0.0693
13.7 22.97 0.0262
13.83 22.96 0.1431
13.96 22.95 0.2769
14.1 22.94 0.4431
14.23 22.93 0.6014
14.35 22.92 0.7669
14.48 22.91 0.9569
14.61 22.9 1.1592
14.74 22.89 1.3754
14.87 22.87 1.6015
15 22.86 1.8271
15.12 22.85 2.0408
15.26 22.83 2.31
15.38 22.82 2.55
15.51 22.81 2.81
15.65 22.79 3.0992
15.78 22.78 3.3792
15.91 22.76 3.6685
16.04 22.75 3.9638
16.17 22.73 4.2631
16.29 22.72 4.5492
16.43 22.71 4.8771
16.55 22.7 5.1585
16.68 22.68 5.4754
16.81 22.67 5.7915
16.94 22.66 6.1185
17.06 22.64 6.4107
17.2 22.63 6.7485
17.33 22.62 7.0862
17.46 22.61 7.4185
17.59 22.59 7.7608
17.72 22.58 8.1062
17.85 22.57 8.4385
17.97 22.56 8.7554
18.11 22.55 9.1408
18.23 22.53 9.46
18.36 22.52 9.7869
18.49 22.51 10.1377
18.62 22.5 10.4977
18.74 22.49 10.83
18.83 22.49 11.0792

Answers (1)

Giorgia Zucchelli
Giorgia Zucchelli on 16 Sep 2013
Edited: Giorgia Zucchelli on 16 Sep 2013
Dear Changlin,
For this type of questions I would recommend to directly contact MathWorks technical support. I will give a short answer, I hope this will help.
Two small things: you need to include the S-parameters at least at the nominal frequency to make sure that the small and large gains are consistent. For example:
S DB R 50
FREQ GHz
* FREQ reS11 imS11 reS21 imS21 reS12 imS12 reS22 imS22
2.10 0 0 11.1494 0 0 0 0 0
POUT dBm
PIN dBm FREQ = 2.10GHz
* Pin Pout Phase(degrees)
0 11.1494 0
1.0000 11.1494 0
2.0000 11.1494 0
3.0000 11.1494 0
If you’d like to have multiple power compression curves at different frequencies, you can try something like:
S DB R 50
FREQ GHz
* FREQ reS11 imS11 reS21 imS21 reS12 imS12 reS22 imS22
2.10 0 0 11.1494 0 0 0 0 0
4.90 0 0 16.1494 0 0 0 0 0
POUT dBm
PIN dBm FREQ = 2.10GHz
* Pin Pout Phase(degrees)
0 11.1494 0
1.0000 11.1494 0
2.0000 11.1494 0
3.0000 11.1494 0
POUT dBm
PIN dBm FREQ = 4.9GHz
0 16.1494 0
1.0000 16.1494 0
2.0000 16.1494 0
You can also use the s2d file format if you prefer (the concept remains the same):
BEGIN ACDATA
# AC( GHZ S MA R 50 )
! small signal s-parameter
% F n11x n11y n21x n21y n12x n12y n22x n22y
2.10 0 0 11.1494 0 0 0 0 0
4.90 0 0 16.1494 0 0 0 0 0
END ACDATA
BEGIN GCOMP7
#AC ( GHZ S DBM MA R 50 )
% F
2.1
% PIN n21x n21y
0 11.1494 0
1.0000 11.1494 0
2.0000 11.1494 0
3.0000 11.1494 0
END GCOMP7
BEGIN GCOMP7
#AC ( GHZ S DBM MA R 50 )
% F
4.9
% PIN n21x n21y
0 16.1494 0
1.0000 16.1494 0
2.0000 16.1494 0
3.0000 16.1494 0
END GCOMP7
With best regards,
Giorgia

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