GB1166105A - High Gain Antenna System with 360° Coverage - Google Patents

Abstract

1,166,105. Aerials. INTERNATIONAL STANDARD ELECTRIC CORP. 14 Oct., 1966 [20 Oct., 1965], No. 45949/66. Heading H4A. An aerial comprises a radio-frequency lens of substantially circular outline enclosed between parallel conductive plates, said lens focusing an incident wavefront to a point near its perimeter, first means for coupling said wavefront to a first half measured in thickness of the lens, second means for coupling energy from the second half measured in thickness of the lens to a focal point, and third means for coupling energy internally between said first and second lens halves. As described, a dielectric lens 4, Figs. 1a, 1b in the form of a circular disc is clamped between two conductive members 1, 2 by means of screws 5 engaging tapped holes in conductive face plates 8, 9 which are cemented to the said lens. The lower member 2 contains a plurality of waveguide apertures 3 whose ends are closed by a conductive septum 4, fixed to the member 2 by screws 7, which is located mid-way in the thickness of the lens 4, and which forms a throat with the underside of the member 1. The waveguides 3 are thus coupled to the lower half of the lens 4 and the throat, which extends into a horn structure constituted by flaring out of the extremities of the members 1, 2, is coupled to the upper half of the lens 4. The said lens is arranged to focus an incident wavefront upon a diametrically opposite waveguide, either by constructing it as a Luneberg type lens or, by approximation, with a uniform dielectric constant. The coupling arrangements are such that there is a substantial measure of isolation between each channel, an equivalent " tee " configuration existing (Figs. 6a. 7a, not shown). In another embodiment, a geodesic type Luneberg lens comprises shaped parallel conductive members 39, 45, Fig. 4b, between which is a parallel dividing member 44. A plurality of coaxial probes 42 is spaced around the lip of the member 39 and the lips of the members 44, 45 are flared out to form a horn. Coupling between the two halves of the lens is provided by essentially circumferential slots 44a and is equivalent to a hybrid configuration (Figs. 6b, 7b, not shown). It is stated that independently available beams covering between them 360 degrees in azimuth are obtainable, and that elevation control is possible by adjustment with a ground plane. The beam shapes may be modified by using suitable baffles and they may have horizontal or vertical polarization. Scanning is possible by energizing the waveguide feeds in succession. The output throats may be coupled to the elements of an aerial array instead of being extended into flared horns.