Wide flare-angle horn antenna with means for radiating low levels of crosspolarisation in two widely separated frequency bands

Preliminary results for a horn antenna with good crosspolar performance in two discrete frequency bands in addition to desirable VSWR characteristics are presented. The horn combines two different design concepts. It uses corrugations to control the crosspolarisation in the lower frequency band when the corrugation depth is approximately /spl lambda//4, and in the upper frequency band when the corrugation depth tends towards /spl lambda//2, crosspolarisation is reduced by controlling the aperture distribution with the addition of the necessary magnitude and phase of the TM/sub 11/ mode controlled by a mode transducer in the input waveguide.