Antennas for the Teledesic system

Summary form only given. The Teledesic system consists of a constellation of communications satellites in low Earth orbit together with a ground network of user equipment and system control terminals. The constellation consists of 288 satellites arranged in 12 circular orbit planes (24 spacecraft per plane) at an orbit altitude of 1375 km. Complete global coverage is provided. The system is designed to provide wideband interactive communications services to a variety of subscribers ranging from the private residential user to the large corporate user. While the range of services extends well beyond those provided by the Internet (e.g. video conferencing), the system is often referred to as a "global broadband Internet-in-the-sky". Further to that description, it is the goal of the Teledesic system to provide seamless, fiber-like communications quality so that the user can not distinguish between the quality afforded by the Teledesic system and that offered by an optical fiber ground network. The Teledesic system operates in the Ka frequency band (20/30 GHz) with a bandwidth of 500 MHz. The various antenna design approaches considered as serious candidates are identified and their characteristics presented and discussed.