A design procedure for classical offset Dragonian antennas with circular apertures

Numerous antenna applications (e.g., remote sensing, radar, and communication) require compact antennas capable of providing a high gain over a wide field of view. Although high performance over a moderate field of view can be achieved with conventional classical offset dual-reflector geometries, some applications require performances unattainable with these antennas. For such cases, the classical offset Dragonian antenna might provide the required improved performance. This antenna employs a paraboloidal main reflector illuminated by a concave hyperbolical subreflector, and its performance has been confirmed. Although Dragonian antennas have been around for more than two decades, to the authors' best knowledge an electrical design methodology is not yet available for them. In this paper a convenient step-by-step design procedure for electrically optimized (i.e., zero geometrical-optics cross polarization and minimum spillover) classical offset Dragonian antennas with a circular aperture is presented. The procedure starts from readily available mechanical parameters and straightforwardly yields an optimum classical design.