find impedance from s-parameter

Is there any easy method or software to find input output impedance of transistor at RF frequencies with help of S parameters?

ADS or Matlab can be a good tool. There are formulas in the Ganzalez's book you can just enter it into Matlab or you can use Matlab RF toolbox

Where to get Matlab RF tool box or ADS?

http://www.mathworks.com/products/rf...cription5.html

You have to buy it. or write a program using formulas in Gonzalez book