GB1390635A - Antennae with adjustable aperture - Google Patents

Abstract

1390635 Aerials LIGNES TELEGRAPHIQUES ET TELEPHONIQUES 19 April 1972 [22 April 1971] 18102/72 Addition to 1352406 Heading H4A An aerial array comprises a plurality of ementary aerials of the kind claimed in Specification 1,352,406, each being fed through a variable phase shifter from a common source. Scanning is obtained by adjustment of said phase shifters, and the angular width of the beam from the array is controlled by adjustment of the currents in the magnetizing coils of the elementary aerials. As described, an array comprises a front current of twelve aerial elements 21 to 32, arranged in three rows and four columns. A similar rear curtain is spaced a quarter-wavelength behind the front curtain, and is fed 90 degrees out of phase therewith. Each aerial element comprises a ferri-magnetic spherical core with an associated magnetizing control winding, and an outer spherical shell of dielectric material. Radio frequency power is fed to a wave source at a point on the surface of said shell. The elements 21, 22, 25, 26, 29, 30 on the left-hand side of the array are fed co-phasally, and the elements 23, 24, 27, 28, 31, 32 on the right-hand side of the array are also fed co-phasally. Scanning may be effected by providing a phase difference between the two halves of the array. This is obtained by means of variable phase shifters 15, 16, 33, 34, 35, 36 which are interposed between a common source 19 and the various elements, and which are controlled by a circuit 37. Said control circuit also adjusts the currents to the magnetizing windings of the aerial elements to maintain, for example, a constant beam width for all scanning angles. As shown, the aerial elements are fed through waveguides, but coaxial or micro-strip lines may be used. In another embodiment, only two spherical aerial elements are used (Fig. 4, not shown). The arrays may comprise rod-type aerial elements, as described in the parent Specification, in place of spherical elements.