simulation antenna + balun

I've done antenna simulation. I recieved s1p file. Balun is described by s4p file (Mini-Circuits). How to connect those blocks to further simulation to recieve s-parameters output port for balun? I don't know how to connect it because s1p file has only 1 port, while balun has 2 input ports. Can anybody help me?

Thanks,
microwave.

you haven't mentioned what you would like to do. what is your goal?

I am guessing you just need to connect the s1p to the corresponding port of s4p, the same way as how you would use them in your actual setup, and terminated the unused ports the same way as you would like do in the actual lab setup.

Since there is a lack of info, that is how far I can offer any help..

The s4p representation of transformer data contains all information about the device, but you can use it directly. It has to be transformed to two port parameters according to the configuration you intend to use, e.g. balanced-to-unbalanced. Then cascading of S-parameter blocks is essentially a matrix multiplication.

My goal is to get the best matching (50 or 70 Ohm) of antenna using balun. Because I can't change construction of antenna, I want use software and simulate different baluns to then use the best result in practice. Every ports of balun are used (there are no unused ports). It has 2 unbalanced ports and 2 balanced ports. I don't know how to connect file which describes antenna with balanced ports to get correct results.


I dont know how to make this convertion, because in real circuit to good work of balun there is needed connection between all 4 ports.



Thank both of you guys for help, much appereciated!

The 4-port measurement is one of several ways to measure balun transformers with a single ended network analyzer. But in the real application the transformer will be used as 2-port device, either unbal-unbal with two terminals grounded or unbal-bal with one side operated in differential mode. The latter case is more comlicated, because a differential port has an associated common mode wave that can be described by s-parameters as well.

If I remember right, the transformation between different S-parameter representations has been discussed at edaboard before. There are tools performing it, but it's a basic algebraic operation that can be derived from the definition of S-parameters.

Thank you very much. I will try to do it the way you suggested. Thanks!


I thought that this transformation can be done by software, if I connect correct these s-parameters blocks.

Yes, of course. ADS e.g. can work with S-parameter files directly. But any circuit analysis software or calculation tool can do, if you put-in the s-parameter equations.

OK.Thank you again.