Free waveguide filter designer

Thaks a lot!
It's very useful...
Anyway I'm involved in a study of squared and rectagular coaxial lines....
Do you have heritage about it?
Can you give me material or some site?
I'm looking for design equations about RF losses and line dimensioning.

Thanks in advance
Lupin

This is useful. Too bad you must use it online.

Can it synthesize a waveguide filter?
Thanks a lot