GB1002140A - Ultra short-wave antennas - Google Patents

Abstract

1,002,140. Aerials. COMPAGNIE FRANCAISE THOMSON-HOUSTON. Feb. 28, 1962 [March 1, 1961], No. 7851/62. Heading H4A. Relates to a directional aerial system comprising an open-ended waveguide or waveguide horn propagating modes of different order which are generated by an abrupt discontinuity in the guide cross-section at the junction between the radiating waveguide and a feed guide of smaller cross-section supporting a single dominant mode. According to the present invention symmetric and asymmetric radiation patterns are produced simultaneously, e.g. for use in a monopulse system, by means of two feed waveguides propagating the same fundamental mode, the longitudinal axes of the feed guides being parallel to and differently displaced from the longitudinal axis of the radiating guide. The radiating waveguide portion 7, Fig. 2, may be of constant or non-constant cross-section and the feed waveguides 8 and 9 may be identical and, as shown, be disposed symmetrically about the mid-section E-plane of the waveguide portion to produce directional patterns in the horizontal plane or, as in Fig. 4 (not shown), be disposed symmetrically about the mid section H-plane to produce directional patterns in the vertical plane. The two arrangments may be combined to produce directional patterns in both the horizontal and vertical planes whereby one of the waveguide portions is divided by a wall 22, Fig. 5, to form the feed waveguides for a plurality of radiating waveguide portions 17, 18, 19, 20.