FDTD analysis of a circular coaxial feeder for reflector antenna

In the frame of the ARTEMIS Program, sponsored by ESA, Alenia have developed a coaxial horn able to generate in the S-band a dual circular polarized signal. The circular polarization was excited within the horn by using four probes suitably fed by a square coaxial network. The horn behavior was experimentally optimized in terms of matching and radiation characteristics. In parallel, a model based on the FDTD method was developed to analyze the electromagnetic (EM) response of the horn. FDTD simulations were carried out in a 3D cylindrical frame best suited for this coaxial geometry. The model implementation for a simplified version of the horn having only two probes is described.