How to determine the parameters of a transmission line for microwave low pass filter?

how to determine the parameters of a transmission line which is to be used to design a microwave low pass filter,with a band edge of 1Ghz and it repeats itself with 5Ghz periodicity.the 3 rd order chebyshev filter is to be used as the prototype..

The best way to determine these parameters is to use the Optimization option of your simulator.