What is the R-C Feedback to this FET?
That, for high open loop gain (e, g. very inductive), sets the voltage gain and lowers distortion.
Imagine a 50 ohm Rsource and that 500 ohm Rfeedback.
Maximum voltage gain is -10x.
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By the way, a resistive feedback will alter the S12 (S_param feedback gain/phase) and perhaps greatly alter the stability factors/circles.