GB594654A - Antenna system for ultra-short waves - Google Patents

Abstract

594,654. Wave-guides; aerials. MARCONI'S WIRELESS TELEGRAPH CO., Ltd. Aug. 8, 1944, No. 15095. Convention date, Nov. 12, 1941. [Class 40 (v)] A radiator, particularly for ultra - high - frequencies, comprises a wave-guide with a horn flaring from the open end, two elements for producing a transverse rotating field in the guide and a circular plate facing the flared surface of the horn and spaced from it. In Fig. 1, a vertical circular waveguide 1, having a diameter greater than 0.67 of a wavelength, is terminated in a trumpet 7 having a horizontal portion 71. Transmitter 4 feeds probes 5, 6 with short-wave energy, the length of the connectors being such that the fields produced by these probes are in phase quadrature. The probes which may be dipoles or loops, are mounted in the same transverse plane at right angles to each other, and since they are excited in phase quadrature a circularly-polarized wave is produced in the guide. A circular plate 8, of metal or material having a high dielectric constant, faces the flared surface 7<1> of the guide and is spaced from it by a distance greater than a half wavelength. This results in a circularlypolarized wave being radiated equally in all horizontal directions.