A circularly apertured dielectric loaded plural mode sectoral horn-an efficient feed for reflector antennas

A sectoral horn suited for a class of reflector (parabolic cylinder) antenna is presented. This horn exhibits low cross-polarization and sidelobe levels similar to corrugated conical horns, but at higher gain or aperture efficiency. The proposed horn is a dielectric loaded plural mode sectoral horn, with a cylindrical aperture. In the development of this horn, the technique of multimode operation for greater directivity at reduced sidelobe and cross-polarization is combined with the technique of dielectric loading for aperture efficiency enhancement on the walls of a circularly apertured sectoral horn with inherently reduced sidelobes as compared to rectangular apertured sectoral horn. The geometry of the plural mode dielectric loaded sectoral horn with a cylindrical aperture is shown. Experimental results of a plural mode H-plane sectoral horn with a cylindrical aperture designed for use in a Cassegrain antenna system for optimum aperture and pattern control in the Ku-band frequencies are presented.<>