Patent GB-1223316-A (GB)
Title: Improvements in high gain antenna system with low side lobes
IPC: H01Q11/06
Filed: 1968-04-11
Abstract: 1,223,316. Aerials. SANDERS ASSOCIATES Inc. 11 April, 1968 [1 Sept., 1967], No. 17616/68. Addition to 1,108,092. Heading H4A. An aerial system comprises two sub-arrays each operating in a different frequency band and comprising a plurality of V-type aerials each of which is formed by a pair of long wire legs and at least one of which converges on a respective feed apex. The aerials of each of the sub-arrays are spatially arranged so that side lobes are minimized and radiation is concentrated in main lobes. As described, two subarrays 202, 204, Fig. 16, are of tandem-V form and are operated over consecutive frequency bands to provide an extended frequency range. The lower frequency sub-array 202 is located above the higher frequency sub-array 204 on six common supporting towers, and each sub-array comprises two paralleled tandem-V form aerials having common feed and terminating apexes, but having their respective side corners off-set, as determined by the distances between towers 223, 223. Thus, the sub-array 202 comprises the aerials 206, 208 and the sub-array 204 comprises the aerials 210, 212. Furthermore, the apex angles of the aerials 206, 208 are made greater than the apex angles of the aerials 210, 212 (Fig. 17, not shown). Resistors may be connected across the respective terminating apexes 216, 220 of the sub-arrays, and their feed apexes 214, 218 are connected to a cross-over network 228 through baluns 232. A transmitter or a receiver may be selected by a switch 230 and be connected to the main input/output port of the network 228. In a second embodiment, the tandem-V form aerials shown in Fig. 16 are replaced by V-type aerials, and in a third embodiment each sub-array is of double tandem-V form (Figs. 4, 5, not shown). In a fifth embodiment, a "parasol" aerial array is formed by long wire legs 242, Figs. 18, 19, extending from a common central tower 244. Each leg consists of two conductors 246, 248 extending radially and downwardly from a feed point 260, near the tower 244, towards the tops of respective end posts 254, 252, and then vertically downward in sections 256 to terminating resistors 258. The array is operated by selecting legs 242 to provide a desired radiation pattern. Thus, as is shown in Fig. 18, a sector 263 may be energized to provide a narrow beam radiation pattern 264. In the section 263 an inner first V-type aerial comprises legs 242d, 242e, a second V-type aerial comprises legs 242c, 242f, a third V-type aerial comprises legs 242b, 242g and an outer V-type comprises legs 242a, 242h. Feed arrangements are described with reference to Fig. 19 (not shown) whereby groups of aerials around the array may be energized successively, so that the beam may be angularly stepped, or simultaneously, for multi-beam operation. By suitably phasing the inputs to the aerials, the sub-arrays may provide either vertically or horizontally polarized radiation. The Specification includes Figs. 1 to 15 which are as in the parent Specification, and it also contains corresponding descriptive matter relating to those figures.