@Stefan Schippers Hi Stefan, I am trying to get S-parameters (loss, gain, noise factor) figures from a LNA circuit. This plot is basically magnitude(db) vs frequency. I could not find any command to do that in ngspice. Do you have any idea how to do it?

If it is a small signal analysis a gain (dB) vs frequency is the standard plot in .ac analysis. See chapt. 15.3.1 of the ngspice user manual.

Actually I found my solution in 17.9. Now trying to figure out the process of finding the value of s11, s12, s21, s22

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