Abstract: A wideband hybrid horn antenna in which a circular section horn (1) is fed by a circular feed guide (3). A dielectric polyrod (7) is cantilever mounted in the throat end (4) of the horn (1) and is tapered to provide a match to the guide (3). Its forward section is tapered from the guide diameter down to about 2 mm just outside the mouth (11) of the horn (1). The various dimensions--horn diameter at throat and aperture, flare angle, polyrod diameter taper and extent--are all chosen to produce a balance of opposing effects on the beamwidth and thus provide a fixed beamwidth substantially independent of frequency over a wide band. A large bandwidth, from 8 to 16 GHz in the particular case, is thus obtained with a substantially constant beamwidth over the band.

Abstract: A microwave polarizer is provided in the form of a wedge at the termination of a rod of dielectric material. Preferably the wedge tapers exponentially in order to provide a good impedance match. Circularly polarized radiation propagating along the rod experiences a differential phase shift at the wedge. This phase shift may be arranged to be 90.degree., so that linearly polarized radiation exits from the wedge. A continuous circular or square guide is used to contain the dielectric rod so that simultaneous orthogonal signals can be converted to or from circular polarizations. Such a wedge termination may be provided at the end of a splashplate or polyrod antenna feed, for a satellite communication system, where right-handed circular polarization is used on the up-link and left-handed circular polarization is used on the down link.