Measurement of phased array fed reflector antenna for mobile satellite communications

Abstract

A satellite antenna must generate high gain and low sidelobe multiple beams for frequency reuse in mobile satellite communications systems using GBO satellites; it must also be flexible in controlling the RF power for traffic variations. We developed a phased-arrayfed large deployable single reflector antenna for this purpose. Our antenna's feed system is constructed with array feeds and a beam forming network (BEN); the array is set at a defocused position. It is very difficult to measure and estimate the performance of this type of antenna because the diameter of the reflector is very large (over 10 m) . We developed a breadboard model (BBK) of the phased-array feed for this system and used a new approach to measure and estimate its performance. We measured the primary feed pattern and the aperture field distribution of the feed array. Using this measured data, we calculated the secondary pattern of the large reflector antenna. We estimated the validity of this method by comparing the calculated pattern with the designed pattern.