Hello Het,
In the directory where uSimmics is installed there is a subdirectory named “doc” in which you find the file “technical.pdf”. This contains a detailed description of all calculations used in uSimmics. The calculation you are interested in is on page 38 under “4.6.2 Gain”. I am not sure if your own calculation is different.
In a first step I recommend in this case not to use the s2p-file to get S-parameter values but to use a diagram to plot all parameters and set markers. Moreover, for doing hand calculations I suggest to use uSimmics itself. In a diagram you can plot a graph defined by your own equation and add a second graph with the max_ulgain_dB(S) function for comparison. That makes it easy to check if your own formula is different from the one used by uSimmics. I did not define an equation in the attached simulation but you certainly get the idea.
Regards
Max
