Fix issue #905 - The matching network tool gives incorrect results when conditionally stable data is provided #907
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As reported in issue ra3xdh#905, the matching network tool gave wrong results when using a conditionally stable S-matrix. In order to have a conjugately match, the device is required to meet the unconditional stability criteria defined in [1] as K > 1 and abs(delta) < 1 A condition was added in the program to filter out these cases and warn the user against this limitation. [1] Microwave Engineering. David M Pozar. 2012. Eqs 12.28 and 12.29
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Tanks for the contribution! Merged. |
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As reported in issue #905, the matching network tool gave incorrect results when using a conditionally stable S-matrix.To obtain a conjugate match at both ports, the device must satisfy the unconditional stability criteria, defined as K > 1 and abs(delta) < 1. See [1].
A condition has been added here. It checks the stability and stops the execution if the criteria is not met.
Tests
1) Conditionally stable device (#905)
Using the S-parameter data provided in #905, a message is now displayed warning of conditional stability and advising the user to consider adding losses and/or FB.
2) Unconditionally stable device.
The device in 1) is stabilized with 12 Ohm at the input. This makes it unconditionally stable (K = 1.06 < 1, |delta| = 0.228 < 1)
The tool is used to synthesise the input and output matching networks. It works as usual: Note that S11 and S22 are matched to 50 ohms at the given frequency (400 MHz).
Thank you @tomhajjar
[1] Microwave Engineering. David M Pozar. 2012. Eqs 12.28 and 12.29