omt waveguide design

hi i am designing a narrow band OMT for dual polarized reflector antenna, preliminry design direction is a circular waveguide with 2 branching rectangular ports, i am wondering now which simulation programs suits me better, FED or FDTD? I have HFSS and quickwave access now, please help me out here, greatlt appreciated, and if there is any good reference material or schematics for OMT design please let me know also, thanks in advance.

On my experience, the best tool for OMT design is WASP-NET or uWaveWizard, HFSS - good choise for narrow band case. I know only one good book for waveguide OMT design:

Waveguide Components for Antenna Feed Systems
by J. Uher, J. Bornemann, Uwe Rosenberg

http://www.amazon.com/exec/obidos/tg...glance&s=books

Best regards,
Kit-the-great

thanks alot :) i also have the book, its by far the best OMT design book, but still its not in detail, i was thinking about using the narrowband type 2 model, if anyone has experince designing omt pls drop a few lines of ur suggestion here, thanks!