How do I measure the group delay of a 2-port series connection in SimRF 3.0.2 (R2011a)?

If I have two S-Parameter blocks in series and each one is specified by an .s2p file (but I do not

have the S-Parameter for the series connection), how can I figure out the total group delay of this series connection? This is where two S-Parameter blocks are connected back-to-back. Would there be a way of doing so in Simulink without having to sum group delays point by point?

Answer 1

[MathWorks Support Team]

For such analysis the recommendation is to use functions within the RF Toolbox.Within RF Toolbox one can use rfckt.series or rfcket.cascade depending on the type of connection of interest. The process for determining the group delay is similar for either one you choose.

For example:

    ckt1 = read(rfckt.passive,'file1.s2p');

    ckt2 = read(rfckt.passive,'file2.s2p');

Then combine the circuits using either of the following:

    combined = rfckt.series('Ckts',{ckt1,ckt2});

OR

    combined = rfckt.cascade('Ckts',{ckt1,ckt2});

Now you can analyze for the group delay, but will need a vector of frequencies:

    analyze(combined,logspace(8,10,21))

To plot the results:

    plot(combined.AnalyzedResult.Freq,combined.AnalyzedResult.GroupDelay)