L-Band Feed Horn and Orthogonal Mode Transducer for the KAT-7 Radio Telescope

The design, simulation and measured performance of a broad bandwidth L-band wide flare angle corrugated conical horn and its orthogonal mode transducer are presented. The feed horn is used on prime focus parabolic reflector antennas of a seven-element interferometer, which is part of the Karoo Array Telescope project. The horn was designed to maximize the sensitivity of the radio telescope over a frequency band of 47.6% relative bandwidth. The orthogonal mode transducer design has low insertion and transmission losses and good isolation, and because of its compact size requires a very small cryogenic cooling system.