Reflector shaping in hybrid antennas

The authors consider hybrid antennas in which a large aperture reflector system is illuminated by a small phased array. The entire feed array is driven with a fixed power distribution at all times, allowing the use of a relatively simple and efficient beam forming network. Particular advantages are to be gained by the use of shaped reflector surfaces in place of conventional conic profiles. In general hybrid antenna performance is dominated by geometrical effects, and thus reflector synthesis based on geometrical optics can be very effective. The description is followed by two illustrative design examples, a single reflector system forming a reconfigurable contoured beam, and a dual reflector configuration for multiple or scanning spot beams