How to add s-parameters from two patches to that of the balun

Hi,

I have an antenna which works on a dual-patch principle. It is powered with a 180 degree phase difference acquired using a balun. The simulation software I use cannot simulate the balun, so I have calculated s-parameters from the two patches separately and would like to cascade it with the balun. I am not sure how to do this with cascadesparams since the two patches are theoretically in parallel. I have attached a diagram of the circuit.

The s-parameters are calculated including the L and C, so towards the left of the inductor (in attached image). I just need to add these two sparameters with that of the balun's

Thanks

Answer 1

[UDAYA PEDDIRAJU]

Hi Vignesh,

I understand that you're looking to cascade the S-parameters of two patches, which are in parallel, with the S-parameters of a balun. To achieve this, you can follow these steps:

1. Import the S-parameters of the patches and the balun into MATLAB as "sparameters" objects.
2. Convert the S-parameters to T-parameters using the "s2t" function for easier manipulation of parallel components.
3. Combine the T-parameters of the two patches by inverting the sum of their inverses.
4. Convert the combined T-parameters back to S-parameters with the "t2s" function.
5. Cascade the combined patch S-parameters with the balun's S-parameters using the "rfcascade" function.

This approach will give you the overall S-parameters for the dual-patch antenna with the balun. I hope this helps!

[Vignesh Radhakrishnan]

Hi Udaya,

Thank you. Unfortunately s2t does not work for just reflection parameters (which is what I get from each patch). It is requires a 2x2xM array.

Do you know to get past this?

Thanks