Mechanically steered tracking antenna for land mobile satellite communications

The key price of equipment in the land mobile satellite communication system is the vehicle antenna, because communication must be maintained while the vehicle moves around in regions within satellite beam coverage. Two types of antennas are considered. One is an omnidirectional antenna for a low-gain application, and the other is a beam-steerable antenna for a high-gain application. For the latter, the authors have developed a mechanically steered tracking antenna which consists of an eight-element spiral printed array, a novel single-channel tracking controller, and an antenna drive mechanism. The antenna performance and its tracking system are presented.<>