Hybrid Reflector-Array Antenna Concept

This paper describes a concept for a hybrid antenna that combines the conventional reflector with an array of printed circuit elements that uses the reflector surface as the array aperture. The objective is to increase the gain and the functionality of the antenna by reusing the conical surface of the reflector as a direct radiating array. The reflector surface can be a single parabolic or a dual reflector surface that uses a combination of conical surfaces. The main reflector surface may contain a conformal printed circuit array with spacing between the conductive elements such that the reflector function is not affected. The gain of the hybrid antenna in a Cassegrain configuration will be a function of the gains of the reflector and the array. The combined gain is reduced by combiner (divider) and blockage losses. The enhanced gain is afforded by magnifying the aperture of one element in the printed array through the reflector system and adding its radiation coherently with that of the direct radiating array. The elements of the printed circuit conformal array are fed with the right phase progression to account for the non-planar surface shape. The paper describes four different arrangements for the hybrid antenna: combined-aperture antennas, dual-band antenna, transmit/receive antenna and dual-beam antenna. Other arrangements can be devised