Abstract:

On the degradation of electrical performance of large shaped Cassegrain antennas by the main reflector deformation, a method for compensation by the moving subreflector is presented. A group of bestfit paraboloids are found by leastsquare fitting the theoretical discrete data. The group of paraboloids are used to fit the deformed main reflector, with the constraint of all these focuses being in line. The bestfit parameters are optimized and the adjustments of subreflector are derived with the ratio of main reflector and subreflector. The adjustments at various attitudes are saved in a lookup table to realtime compensate for main reflector deformation. From the experimental verification on a 64 m reflector antenna, satisfactory results are obtained.