Wideband feed systems for radio astronomy

Increasing requirements in radio astronomy for wide band observing, highly compact feed systems, and remote telescope operation are stretching the capability of traditional horn antenna and feed system designs. Here we describe the development of some new types of feed system for Australian and overseas radio telescopes designed to meet these requirements. The feeds systems described are 4 to 12.25 GHz smooth-walled feeds for Cassegrain and Gregorian dual-reflector telescopes, and a highly-compact 700 to 1700 MHz prime focus feed.