I was checking stability of a differential single stage amplifier, obviously I had 50-ohm port in 50-ohm port out, I checked K which at some frequencies was below one, which means potentially unstable, but B1f was greater than zero at all frequencies.
Gonzalez microwave book states K>1, |delta|<1 for unconditional stability of a two port, and also states you can combine with B in which if it is greater than 0, is equal to necessary and sufficient condition stated earlier.
My question is how can I know what is B1f in sp analysis? Is there similar approach to spectre -h xxx that I can do to find out?
The B in Gonzalez is 1+|S11|^2-|S22|^2-|delta|^2
ADE flavor : ADE Assembler
SPECTRE_21.10.389
IC06.18