Omnidirectional Dual-Reflector Antennas for Flexible Coverage

This letter discusses the design of an omnidirectional dual-reflector antenna, where the main reflector has a circular generating curve. Under geometrical optics approximations, the subreflector is shaped to produce a uniform phase distribution on a cylindrical aperture placed in front of the main reflector to maximize radiation on the horizon line. Closed-form design equations are presented for the subreflector shape. To provide the scanning of the main beam direction along the vertical plane, the displacement of the subreflector along the symmetric axis is explored. For the analysis of the antennas, method-of-moments technique is employed .