A circular horn with dielectric coated flange

The similarity of a horn with corrugated flange and a horn with dielectric coated flange is discussed. Radiation characteristics of a circular horn with dielectric coated flange excited by a circular guide is then investigated experimentally. It is found that by a proper selection of the various elements — the waveguide radius, the distance from the waveguide aperture to the dielectric surface, the airgap thickness and the size of the flange — the E and H plane radiation patterns, the side and back lobe radiations and the bandwidth of the antenna can be controlled. These characteristics are found to be very similar to those obtained from a circular horn with corrugated flange. Some experimental data is given, as well as discussion of the usefulness of this antenna as a feed for paraboloidal reflectors.