On the design of reflector antennas for cosecant squared power pattern

The characteristics of a reflector antenna radiating omnidirectionally in azimuth with a cosecant-squared power pattern in vertical planes, as intended for point-to-multipoint services in the millimetric wave range and comprising a single circularly symmetrical shaped reflector surface fed by an axial horn, were presented in a previous paper (see IEEE Antennas and Propagation Society Symposium Digest, vol.3, p.2154-7, 1999), as an alternative to configurations reported elsewhere, involving nodal stations with up to four antennas for quadrant sectors coverage or dual reflector arrangements for omnidirectional coverage. Reported results, considering a rigorous feed model for the constructed prototype, then highlighted the main features of the proposed design. The present work extends the previous investigation by considering the effect of employing larger feed apertures yielding more collimated primary fields, with a view towards synthesizing more compact reflector surfaces.