High efficiency phased array feed antennas for large radio telescopes and small satellite communications terminals

Aperture-type phased array antennas offer the capability to steer beams electronically, but cost far more per unit collecting area than a shaped metal dish. A compromise between these extremes can be achieved by using reflector antennas with phased array feeds. A key research issue for array feeds is that phased array feeds are typically less efficient than traditional horn fed reflector antennas. If the efficiency and noise performance of a phased array feed is suboptimal, the performance gain of electronic beam steering is outweighed by the degradation in signal to noise ratio relative to a traditional horn feed. This paper reports on recent work aimed at realizing ultrahigh efficiency phased array feeds for two applications with the most demanding possible efficiency requirements: astronomical imaging and satellite communications.