Dual Band (S-X) Ground Station Antenna for Low Earth Orbit (LEO) Satellite Tracking Application

Design and realization of a dual band, dual polarized composite monopulse tracking feed, covering S- (2.0-2.3 GHz) and X-band (7.8-8.5 GHz) is reported in this article. X-band feed is a five element monopulse feed, comprising a corrugated horn acting as the main or Sum element surrounded by four circular septum polarizers serving as tracking elements. S-band feed is a four element monopulse feed consisting of square dielectric array arranged in
$2\times 2$
configurations. Illumination efficiency of the proposed composite feed, positioned in the same Cassegrain plane, is above 90 % for both the bands. S/X composite feed is systematically designed, fabricated and experimentally characterized revealing excellent correspondence with the simulated result. The realized composite feed is installed in 7.5m antenna system at NRSC Hyderabad, ISRO, India and currently fully operational. Expected / targeted G/T of 32 dB/K is achieved with the realized antenna system. The proposed feed is highly efficient, compact, simple and cost-effective, uses generic design style and perfectly suitable as ground station reflector feed antenna, meeting stringent industry specification.