GB1341512A - - Google Patents

Abstract

1341512 Aerials SINGER CO 5 May 1972 [16 Aug 1971] 21042/72 Heading H4A A multiple beam planar aerial comprises an elongated leaky waveguide and two elongated feeder waveguides, each having a plurality of slots communicating with said leaky waveguide. As described, spaced apart feeder wave guides 21, 22, Fig. 2, have respect pairs of input ports 31, 32 and 33, 34 and are provided with edgecut arrays of slots on their facing sides. A leaky waveguide 41 extends between the waveguides 21, 22 and is constituted by an array 42 of parallel metal strips 45 which are photoetched on a dielectric plate, a contoured metal ground plate 43, and side walls 44. Dielectric or metallic spacers 61 inside the waveguide 41 extend between the dielectric plate and the ground plate. Absorbers 46 may be disposed along the side walls 44 to reduce undesirable reflected energy. Additional wires or strips 60, Fig. 7, which are orthognal to the strips 45, may be provided in the vicinities of the feeder waveguides 21, 22, in order to reduce radiation of cross-polarized energy. The aerial may be installed in an aircraft and be used in a lobeswitching Doppler navigation system (Fig. 1, not shown). Any of four beams can be radiated, according to which input port is excited.