On the design of ground-based radiometer antennas

This paper deals with the design of ground-based radiometer antennas. In order to investigate the interaction of the antenna pattern with its noisy surroundings, a model for the brightness temperature of the environment is presented. This is followed by a description of a method for finding a template for the antenna pattern which assures a prescribed measurement accuracy. Therefore, different contributions of the antenna to the uncertainty of the measured brightness temperature are discussed, such as those due to the sidelobes, the non--zero beamwidth and the pointing errors of the positioner. A theoretically optimal antenna configuration is presented and the performance parameters of two often applied reflector antennas are compared with those of the optimal system. Finally, the resulting radiometer-antenna design procedure is presented