The original work was published in the article:
"S-Parameter Output from SPICE Program" (Goyal, R., IEEE Circuits and
Devices, March 1988, pp.28,29)
It was also published at a later date in one of the popular
trade mags (which I still don't remember).
Here is a simple spice deck which implements the method.
Caveat Emptor, your mileage may vary and the rest of the usual disclaimers....
* derived from R. Goyals article"
* "S-Parameter Output from Spice Program"
* IEEE Circuits and Devices March 1988, pp. 28-29
* Connect driving signal to node: input
* Connect DUT to node: in
* Measure S11 at node: S11
vdrive input 0 ac 2
* Measure S11
Gin in 0 input 0 -0.02
Rin in 0 50
Eovr mix 0 in 0 0.4
Edel mix s11 input 0 0.2
Rmes s11 0 1
* Device Under Test
Rdut in 0 50
Cdut in 0 20pF
.ac lin 100 1MEG 1000MEG
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