the integration of one 3 port network and two 2port network

I want to integrate a T junction and two waveguide filter into a diplexer,with no aid of software. I have got the S parameter(complex) of T junction and the waveguide filters.but how to got the S parameter of the diplexer?
It is a problem of microwave network synthesis. I know the method to connect two
2port network with a transform between ABCD matrix and S matrix.but as to the 3port problem, I cant find a book describes the method?anyone help me?
thanks

Hi,

I can think on two methods

First is to convert your S parameter matrices into chain wave matrices (T matrix). Then you can use matrix multiplication to get to chain matrix of overall network. This has to be back transformed to S matrix at the enc. You can use some mathematical software with symbolic capability to derive equations.

The other method is to use signal flow diagram.

Some books on the first method:

Dobrowolski-Introduction to Computer Methods for MW Circuit Analysis and Design
Hong and Lancaster-Microstrip Filters for RF/Microwave Applications

Second method is covered in Pozar's book.

flyhigh