Simulations and Measurements of a Circular Waveguide Septum Feed

This is the first of two articles describing a number of time domain solver 3D EM field simulations of an antenna feed consisting of a circular waveguide with a septum polarizer and two external coaxial connector ports. Measurements of the actual S-parameters of a constructed feed were then compared to the simulations, to determine which mesh and solver settings afforded good accuracy without excessive computation time. This first article concentrates on the feed alone without a reflector. Significant energy is reflected back into a feed when it is placed at the prime focus of a parabolic reflector. To exmine these effects, the second article will concentrate on modeling and measurement of the entire antenna.