RF: De-embed S parameters

Hello all, I have my circuit block diag as shown below:

I already have the 's_params' matrix values(measured). I need to de-embed this to get the s parameter values of my DUT: 's2_params'. Using matlab, I have found this equation:

    s2_params = deembedsparams(s_params,s1_params,s3_params)

=> t_params = t1_params * t2_params * t3_params

And as for the t1_params, t3_params is concerned, I have designed another compensation circuit and have the s paramater values of it (namely s_compensated-->s matrix,t_compensated-->T matrix). So, I could say, t_compensated = t1_params * t3_params The compensation circuit is actually symmetric. So t1_params = t3_params as for my design.

My question here is, in the equation: t_params = t1_params * t2_params * t1_params, t_params is known and I need values of t2_params. In the equation: t_compensated = t1_params * t1_params, t_compensated is known. From this, I need to get values of t1_params and substitute in first equation to get my DUT value (i.e., t2_params).

But to divide t_compensated matrix value into t1_params*t1_params, I need to take a square root of it, but the square root of matrix yields 4 possible roots, and for each of these I would get different t2_params after substitution. So can someone help me with how to get t2_param values in my case?

Answer 1

[Vidya Gopalakrishnan]

https://www.mathworks.com/help/rf/examples/de-embedding-s-parameters.html