Design of omnidirectional dual reflector antenna: Case of the main reflector with circular generatrix

This work considers the synthesis and analysis of dual reflector antennas designed to radiate omnirectional radiation patterns. The reflectors are circularly symmetric concentric surfaces. Here, the case of the main reflector obtained from a circular generating curve is considered. By applying Geometrical Optics approximations, The main reflector is kept fixed and the subreflector is shaped to produce different tilt angle of the main lobe radiation pattern over the horizon line, considering a uniform phase distribution on a conical aperture placed in front of the main reflector. Depending on the type of ray mapping between the reflectors, two kinds of configurations are identified. By employing the aperture method, the performance of these antennas is predicted and a full wave analysis based on Method of Moments analysis is employed to validate these results.