In this demo, we use GEMS to simulate a dual mode horn antenna, which is frequently used as a feed of a reflector antenna. The horn is excited by using TE11 which will generate TM01 at the horn aperture. The TE11 and TM01 have the same amplitude and opposite phase at the horn aperture, therefore, this horn has a very low side lobe in its far field pattern.  Since the horn is infinitely long at the feed side, GEMS uses a terminator (matched load) to terminate the circular waveguide so that we can calculate the full 3-D far field pattern

 

Download simulation guide (PDF)

Download project file (gpj