How can I create an s2p file for simple LC matching circuit

I never generated an s2p file (touchstone file), I wonder if you can recommend me a software that I can use to generate the S-Parameters for a simple LC Matching circuit I need for antenna impedance matching network! Is there any free software for such thing?!

I am using FEKO for designing the antenna and it allows generating a general network through importing its s2p file. So I need a software to generate the S-Parameters for my antenna impedance matching network.

The free Sonnet Lite EM simulator can also do netlist analysis, in addition to EM analysis.

Edit > New Netlist

Create your netlist and specify Touchstone *.s2p in the menu: "Analysis > Output Files ..."

http://www.sonnetsoftware.com/products/lite/

Thanks a lot. This Sonnet software is great and easy to use.