Currently designing a differential LNA schematics in virtuoso, my issue is at the output I am using a VCVS. while trying to plot "Kf (stability factor)" it gives no plot, since S12 is zero while using a VCVS making "Kf" infinite. Is there any other way to check unconditional stability? or is there a way to plot "Kf" with a VCVS?
Regards