Multibeam satellite communication antenna

An antenna comprising a spherically-contoured reflector, having a radius of curvature and a reflective surface towards the inside of the sphere; and a feed assembly, comprising (i) a spherical aberration correcting secondary reflector, and (ii) a feed element. The reflector and feed element are placed such that their axes of symmetry are co-linear and lie upon a line passing through the centre of a sphere, corresponding to the spherical contour of the primary reflector, and the centre of the secondary reflector. The secondary reflector is positioned and shaped such that all possible ray paths, starting from the feed and travelling to the secondary reflector from which they are reflected to the primary reflector, become the same lengths, such that a point source radiator illuminating the secondary reflector and there from the primary reflector, produces a collimated quasi-plane wave. Also described is an antenna system comprising a plurality of spherically contoured reflectors, each having a radius of curvature and an aperture, and one electro-mechanically scannable feed per reflector, each having an azimuthal and an elevational angle scan range. The radius of curvature and the aperture size of the reflectors are individually configured to (i) achieve a desired gain and communications link margin, and (ii) cover the entire elevation and azimuthal angle scan ranges of the feeds, such that any Poynting vectors directed between a feed and a corresponding satellite in the sky is not obstructed by any portion of the reflector.