RF Circuit (rfckt) is an open-source MATLAB suite for simulating and analyzing two-port RF networks is the frequency domain. Circuits are described by a cell matrix listing cascaded components and parameters.
Download the zip file and then look at the pptx file to see how to install. It's pretty simple: unzip the zip file and then add that directory with subfolders to your MATLAB path. Look through the 5 example scripts to get an idea of how to use this suite. Additionally, you should read the help for the ckt_abcd() function.
Feel free to email me if you have any questions or problems.