GB709351A - Radio frequency antennae - Google Patents

Abstract

709,351. Aerials; aerial coupling arrangements. STANDARD TELEPHONES & CABLES, Ltd. July 11, 1952 [July 21, 1951], No. 17562/52. Classes 40 (5) and 40 (7) An antenna system comprises a first conductor spaced a small distance above a second wider conductor, the wider conductor having openings there'n across which the first conductor extends whereby part of the energy propagated along said conductor is radiated by said openings. In one embodiment the first conductor 1 is a continuation of the centre conductor of a feeding co-axial cable 5 and is spaced a small distance above a ground plate 2 connected to the outer conductor which forms the second conductor. Slots 3 are cut in the plate 2 and form a radiating array across each of which the conductor 1 passes to energize it. A termination 4 is provided physically supporting the end of member 1 and electrically comprising either a matching impedance or a short circuit. Fig. 3 (not shown) shows an array in which the conductor 1 is forked each part passing over a series of slots similar to those shown in Fig. 1. The embodiment shown in Fig. 4 is one designed to give circular polarization. In it slots 11 and 12 are formed in the ground plate at right angles to each other and at positions spaced apart an odd multiple of a quarter wavelength along the conductor 1. The conductor and the ground plane containing the openings may comprise layers of conductive material printed, embossed, or photographically applied, to opposite sides of a dielectric supporting member. The termination may be an extended area forming a capacity or an inductive stub, Figs. 5 and 6 (not shown). In a further embodiment, Figs. 7 and 8, the ground plate 18 is between two layers of insulation 21 and 22 the outer sides of which carry respectively conductors 19 and 20 crossing slots 23 and 24 in the plane 18. Conductor 20 extends unbroken as one conductor of the feeder and the other conductor of the feeder 25 is directly connected to the slotted ground plate 18. Conductor 19 is led down over a slot 29 in conductor 25 and is terminated by being shorted to that conductor by a connection 28 quarter of a wavelength beyond the slot. It is energized through the slot by conductor 20 which passes across the slot on the opposite side. The insulating materials 26 and 27 spacing the conductors are selected to have differing constants so that the voltages on lines 19 and 20 are 180 degrees out of phase. Specifications 704,050 and 708,601, [both in Group XL(b)], are referred to.