GB1219543A - Antenna system - Google Patents

Abstract

1,219,543. Aerials. MATSUSHITA ELECTRIC INDUSTRIAL CO. Ltd. 29 Jan., 1969 [31 Jan., 1968; 15 Feb., 1968 (3); 18 Nov., 1968 (3)], No. 5040/69. Heading H4A. An aerial system has at least two elements, which respond to vertically and horizontally polarized waves respectively, and an active solid state circuitry, which has functions of impedance transformation or amplification or both, and which is located either at the junction of the elements, or half way along one of them. As described, an aerial system comprises vertical and horizontal elements 13, 14, Fig. 4, above a ground plane 11, and an active solid state circuit 16 including, for example, one or more transistors, connected at the junction of the said elements. One terminal of the circuit 16 is earthed, and the far end of the horizontal element 14 may be earthed through an impedance 15 to increase the operating bandwidth. The lower end, or driving point, 12, of the element 13 is connected to one terminal of a load 18 (e.g. a receiver) the other terminal of which is earthed. The active circuit enables matching to be improved and the directivity of the aerial system to be controlled. In other embodiments, the straight horizontal element may be replaced by a helical element, which may have a ferrite core (Figs. 6, 7, not shown). The active circuit may be located midway along an aerial element, instead of at a junction of aerial elements. An embodiment is described in which a single horizontal aerial element (14), Fig. 14 (not shown), has active circuits (16), (28) at each end, which are con. nected also to respective vertical aerial elements (13), (27). Various means of feeding an active circuit comprising a transistor are described using either two conductors forming a two-wire transmission line (Fig. 8, not shown), with which may be associated a third conductor (Fig. 9, not shown), or a coaxial cable (Figs. 10, 15, not shown, or Fig. 11). Thus, a transistor 16, Fig. 11, has bias resistors 25, 25<SP>1</SP> and a D.C. load 21, and its base is connected to a horizontal aerial element 14. The outer sheath of a coaxial cable 26 functions as a vertical aerial element and D.C. power is fed to the transistor 16 via its centre conductor and an intermediate sheath. A load 24 is connected to the lower end of the outer sheath of the cable 26.