Efficient aberration correction with a transverse focal plane array technique

The experimental results of investigation and utilization of the focal-region-field distribution of a Cassegrain antenna are presented. Aberrations caused by beam scan or reflector distortion can be significantly reduced through control of the phase and amplitude of feed sources distributed in the focal plane and transverse to the system axis. Inherent in this technique is the capability to correct for aberrations and also insure maximum antenna efficiency. A tubular feed array is used both as a probing instrument to determine the required focal-field distributions and as an active feed in which the phase and amplitude of the individual elements are independently controlled. The results are applicable to other reflector and lens antennas.