My concern is that we should judge the sign of imag(acos(alpha(gh)),but not for (imag(alpha(gh))). By the way have u ever simulated for cELC structure, how about the extracted parameter from S parameter.
I have posted an entire lecture on this topic that covers a bunch of different approaches. You can get the lecture notes and watch a recorded lecture here:
Your lecture notes are simply beautiful. Thanks for the effort. Can you also include your simulation examples (CST or whatever) and your Matlab code for effective parameter retrieval? This would be a tremendous help. Thanks.