A large L-band rectangular corrugated horn

A lightweight, rectangular, corrugated-horn antenna constructed from sheet metal is described. Over a 1.3-1.7 GHz operating band, its half-power beamwidth is approximately in the -plane and varies from to in the -plane. Quarter-wave choke slots at the aperture help to reduce the -plane sidelobes below -55 dB at angles greater than , while the -plane sidelobes lie in that range both with and without choke slots. Return loss throughout the operating band is -25 dB or below. Critical dimensions are provided, together with useful guidelines for designing similar antennas.