Axis-Displaced Dual-Reflector Antennas for Omnidirectional Coverage With Arbitrary Main-Beam Direction in the Elevation Plane

The synthesis of classical dual-reflector antennas suited to provide omnidirectional coverages with arbitrary main-beam direction in the elevation plane is discussed. Both sub- and main reflectors are bodies of revolution generated by axis-displaced conic sections, so to transform a spherical radiation emanating from the antenna principal focus (at the symmetry axis) into an equiphase field distribution over a conical aperture. Closed-form design equations are presented for the geometric-optics synthesis of all possible configurations. Several case studies are investigated and analyzed by the accurate method of moments technique in order to validate the proposed design procedure