Performance of an Axially Displaced Ellipse Reflector Antenna With Compact Monopulse Tracking Feed for a Small Aperture Transportable Terminal

Performance of an axially displaced ellipse (ADE) reflector antenna with small aperture (≈33 λ0) when integrated with monopulse tracking feed is presented for the first time in this article. The results and other system design aspects are compared with the conventional geometries like Prime Focal, Gregorian, and Cassegrain antennas indicating significant electrical and mechanical advantages for a small aperture. These enable the design of a 4.6 m-diameter compact auto-tracking ADE antenna at S-band for deploying on a transportable terminal. The measured gain of the antenna is 37.6 dBic at 2.25 GHz, which corresponds to an aperture efficiency of about 50% and gain over noise-temperature (G/T) ratio is 15.3 dB/K. The measured null depth is 30 dB with respect to the peak for monopulse tracking. These values are very good considering the small size of the aperture and the complexity of the feed.