In 2020, Keysight Technologies presented a webinar with a comprehensive review of 28 approaches to stability analysis.   Tom Winslow explains the need for a new probe to replace traditional S-Probes used in circuit simulations.  The ADS design software incorporated a Winslow S-Probe component (WS Probe).   See the webinar, Designing for Stability in High Frequency Circuits,  here .   There is an additional webinar by Matt Ozalas,  Everything High Frequency Circuit Designers Need to Know About Stability Analysis,   here .

In the slides below , QucsStudio is used to duplicate the passive network test shown in the webinar.