Hi there,
Suppose that I have a one-port s-parameter measurement (or simulation) data of a transmission line with one side terminated open, what is the best way to estimate its two-port s-parameters?
byoung
It is not possible to calculate the 2-port S-parameters from that single 1-port data.
If you are sure that your line is well matched (S11 close to zero), a rough estimate is that unterminated S11 is two times the lines insertion loss (S21)
Generally it's not possible. You can try to fit a transmission line model with limited number of parameters (e.g. Z0, electrical length, attenuation) to the S11 measurement.
It is not possible to calculate the 2-port S-parameters from that single 1-port data.
If you are sure that your line is well matched (S11 close to zero), a rough estimate is that unterminated S11 is two times the lines insertion loss (S21)
Thanks for the comment! Yes, I agree to your comment. However, recently I learned that Keysight has a software that can do the estimation. Basically, it is to provide a simple way for deembedding of EVB traces. All you need is just one-port s-parameter data with one side open. I took two-port data from one-port measurement one using the tool, and then compared it with (original) two-port measurement data, and it is not perfect, but they are reasonably well matched, which surprised me. :-o I am wondering about the principle of work.
Generally it's not possible. You can try to fit a transmission line model with limited number of parameters (e.g. Z0, electrical length, attenuation) to the S11 measurement.
As stated, it can work with a model based approach. You need to put in multiple s11 points to identify e.g Z0 and length. You can play around with circuit simulator and a transmission line model to see how the s11 curve depends on Z0 and length.