Symmetrical dielectric loading onE- andH-plane walls of a rectangular horn for pattern shaping

Abstract

Analytical and experimental results of a highly directional antenna feed with a beam shaping facility are presented. The antenna consists of a hybrid mode dielectric loaded rectangular horn that utilizes the technique of combining several higher order modes for pattern shaping. The amplitudes of the various modes in the waveguide are determined by means of modal expansion of fields for a known symmetrical throat excitation. The modes thus obtained are used to evaluate the radiation patterns derived by the aperture field method on the basis of the vector diffraction formula. The significance of higher order mode content in shaping the radiation patterns of dielectric loaded horn is demonstrated first for symmetrical dielectric loading on H-plane walls and E-plane walls separately and then for symmetrical dielectric loading on both E- and H-plane walls for considerable control over the E- and H-plane patterns.