Feeds for microwave reflector antennas

The principles and design of feeds for microwave reflector antennas are explained with description of recent major developments in feed antennas. The feed is one part of a reflector antenna and the uses and principles of operation of the reflector antenna are described with particular reference to antennas for satellite communications. The electrical design parameters for feeds are explained, including pattern symmetry and cross-polarization. A description of simple horn feeds is followed by a discussion of corrugated horns and the reasons for their use as high performance feeds. The design constraints and manufacturing problems of practical horns are explained. The simple ring feed for low cost reflector antennas is described. The paper finishes with a brief discussion of array feeds as will be used on future satellite reflector antennas.