Design of hollow dielectric pyramidal horn antennas

Abstract

Over the years much research work has been carried out on dielectric-loaded horns of different geometries to obtain high efficiency, low crosspolarisation, low side lobe levels, enhanced bandwidth and pattern shaping capabilities by controlling the amplitude and phase distributions over the aperture. Palit et al. (see JEEE, Aust., vol.16, no.2, p.139-46, 1996) have derived radiation fields of solid-dielectric and dielectric-loaded pyramidal horns using the step approximation method and found that the computed far field patterns are in good agreement with the measured ones. It seems not much significant work has been done on hollow dielectric pyramidal horn which is light in weight and can find useful use in radio astronomy and satellite communications as a primary feed. The author designs and confirms the step approximation analysis technique by deriving and computing the radiation fields of the hollow dielectric horn and comparing the values with the measured ones. The field components are derived for hybrid TE/sup x//sub mn/ modes by solving Maxwell's equations. It is found that the computed patterns using Schelkunoff's equivalence principle agree well with the measured patterns.