A design procedure for classical offset inverse Cassegrain antennas with circular apertures

The classical offset inverse Cassegrain configuration is proposed as a reflector antenna geometry. Its sub and main reflectors are concave ellipsoid and convex paraboloid, respectively. This geometry is potentially capable of yielding a wide field of view while being efficiently illuminated by small feeds. An efficient design procedure was derived for them, and verified with two examples. The starting design parameters of the procedure are convenient since they can be easily related to basic system constraints. The scattering characteristics of the two examples validate the design procedure by indicating that all optimum geometry has been obtained.