Design of flared-horn primary feeds for parabolic reflector antennas

The paper describes the derivation of a simple design procedure by which the dimensions of a rectangular flared-horn primary feed, operating in the TE10 mode, may be determined for parabolic reflectors, having any f/d ratio and with either a rectangular or circular contour, so that maximum aperture efficiency is obtained. The design technique is based on achieving a best match between the principal component of the reflector focal-plane electric field and that electric field existing in the horn mouth during transmission. In addition, the design procedure predicts the value of the spillover power, the reradiated power, the relative edge-field illumination, the resultant reflector aperture-field distribution and the value of the maximum aperture efficiency obtainable for the given combination of horn feed and reflector.