GB1352406A - Antennas with adjustable aperture - Google Patents

Abstract

1352406 Aerials LIGNES TELEGRAPHIQUES ET TELEPHONIQUES 13 July 1971 [30 July 1970 14 Jan 1971] 32889/71 Heading H4A An electronically controlled adjustable aperture aerial has a primary excitation means associated with a radiating structure made of a first part of a non-magnetic dielectric material, and of a second part of a ferrimagnetic dielectric material with at least one magnetizing coil through which a control current may be passed. In a first embodiment a tapered dielectric rod 1, Fig. 1, having probe and cap feed means 2, 3 is provided with two ferrite rings 4, 5 which are associated with respective magnetizing windings 4<SP>1</SP>, 51. More than two rings may be provided (Fig. 2, not shown) or the rings may be replaced by a coating on the dielectric rod of a ferrimagnetic material. In other embodiments, a spherical shell of non-magnetic dielectric material surrounds a core of ferrimagnetic dielectric and the materials and dimensions of both the shell and the core may meet a stepped approximation of Luneberg's law. Thus, as shown in Fig. 9, a spherical shell 18 of dielectric material surrounds a sphere 12 and two concentric shells 17 1 , 17 2 all of ferrite material, and having respective magnetizing windings 19, 211, 21 2 . Feed means comprises a waveguide 14 having a flange 15 shaped to fit the outer surface of the shell 18. The three ferrite members may be combined to form a sphere, with a single magnetizing winding (Fig. 8, not shown) and in a modification thereof, for latching operation, the winding is of toroidal form, passing through a diametral hole in the ferrite sphere (Figs. 10, 10A, not shown).