waveguide example

I am having trouble setting up a circular waveguide simulation properly. I can get a rectangular waveguide simulation to run fine. If some one would not mind, I would appreciate an example of the setup, preferably in the form of an HFSS file that I can run the simulation and see what I was doing wrong.

Thank you.

If you are running HFSS and using a modal wave port you probably need to ask for more modes. Circular guide is mode rich and has numerous modes that do not have rectangular counterparts.