Re: 2-port stability
I found the answer by myself:
"A related parameter μ' can also be used, it is always bigger than one when μ is, so it doesn't give new information for the purpose of determining unconditional stability"
source:
**broken link removed**
Similar conclusion I came as well as I read the original IEEE paper "A new criterion for linear 2-port stability using a single geometrically derived parameter" by Marion Lee Edwards.
So it enough if mu>1, there's no need to calculate mu_prime.