Antennas Fed by Horns

Formulas are derived for the E- and H-plane radiation patterns of antennas fed by horns as functions of illumination taper. The case of a single lens or reflector antenna fed by two contiguous horns stacked in either one of the principal planes is then investigated. By means of an illumination factor defined in terms of physical dimensions, the following electrical properties are related: (a) loci of half-power beamwidths, zeros, and side lobe peaks, (b) illumination taper at edge of secondary antenna, (c) crossover power, (d) spillover power, and (e) gain referred to the feed horn.