Resonator Effects in Microwave Cassegrain Antennas.

摘要

The effects of standing waves in the region between the feed horn and subdish of a Cassegrain antenna are examined experimentally. Evaluation of the experimental results indicate the existence of a resonator in this region which makes calibration of the Cassegrain antenna necessary in order to determine the influence of the resonator on a signal which is transmitted or received. It has been established that the radiation pattern characteristics are profoundly influenced by the location of the feed horn with respect to the parabolic (main) reflector. These two effects (the horn-subdish resonator effect and the primary feed pattern alteration caused by the main reflector) are judged to be the dominant factors influencing the observed on-axis oscillations occuring with changes in the feed horn-subdish spacing. The influence of multipath has been examined and so far as can be determined by this study is not a contributing factor.