GB372319A - Improvements in or relating to directional wireless aerials - Google Patents

Abstract

372,319. Directive wireless signalling. WILLIAMS, W. E., Kildare, Ethelbert Road, Bromley, Kent, and BRITISH RADIOSTAT CORPORATION, Ltd., 29, George Street, Hanover Square, London. Jan. 31, 1931, No. 3167. Addition to 317,301, [Class 40 (v), Wireless signalling &c.]. [Class 40 (v).] The parent Specification describes a group of individually directive aerial units with a lateral " displacement " in a direction perpendicular to the direction of maximum radiation of each unit, of the order of one wavelength divided by the sine of the angle between the direction of the principal diffraction maximum of a unit and the direction of first minimum. The units also have " separation " in the direction of maximum radiation of each unit. The present invention comprises a second similar group of aerial units wherein the displacement is in the opposite direction to that of the first group, e.g. one group is arranged as a mirror image of the other. In one embodiment the units 10, 11 each comprising four aerials form one group and the second group 13, 14 is arranged as shown in front elevation in Fig. 1 and in plan in Fig. 2, the direction of maximum radiation being indicated at 12. The vertical displacement between the groups may be the same as the lateral displacement between the units. In another embodiment, Fig. 3, each aerial unit is constituted by two rows of radiations 10, 10a, 11, 11a, 13, 13a, 14, 14a. Each linear array comprises a plurality of elements spaced one wavelength apart and the two linear arrays of each unit are separated by half a wavelength. The separation between the units of a group is one-quarter of a wavelength. The parts 10, 13 are preferably excited in phase and also the parts 14, 11 but 90‹ out of phase with parts 10, 13, also the parts 10a, 13a in phase but 180‹ out of phase with parts 10, 13, and the parts 14a, 11a in phase but 180‹ out of phase with parts 14, 11. In a further elaboration, Fig. 6 (not shown), four complete arrays such as that shown in Figs. 1 and 2 are arranged one pair above the other.