Historical and Planned Uses of Antenna Technology for Space-Borne Microwave Radiometers

This paper reviews the historical and future uses of antenna technology for space-borne microwave radiometers. The radiometer antennas are discussed, starting from the Dicke-type radiometer, as used in the Microwave Sounder Unit (MSU), to the present-day total-power radiometer. The antennas cater to the need for very high beam efficiencies, of the order of 95% to 98%. The paper also summarizes the specifications, design issues, and the performance of various radiometer antennas.