GB1332151A - Aerial arrangements and feeding systems therefor - Google Patents

Abstract

1332151 Aerials MARCONI CO Ltd 19 April 1971 [9 Jan 1970] 1078/70 Heading H4A An aerial feeding system comprises two hybrid circuits 5, 7, Fig. 2, which are interconnected by two variable phase shifters 11, 12. Input is applied to one input terminal of the hybrid circuit 5, the other input terminal being connected to a matching load 6, and outputs are obtained from the output terminals of the hybrid circuit 7 for differently oriented aerial arrays 3, 4. Each phase shifter 11 or 12 has separately controlled 90 degree and 180 degree phasing sections and commonly controlled 22À5 degrees and 45 degree phasing sections. The hybrid circuits 5, 7 are of the kind in which an input results in two equal outputs having a 90 degree phase difference. With this arrangement, either the aerial array 3 or the aerial array 4 may be energized by suitably setting the phase shifters 11, 12. For example, if the phase shifter 11 is set to 90 degrees and the phase shifter 12 is set to 270 degrees, the fraction of power fed via the former to the array 3 experiences a phase change of (90 degrees + 90 degrees) = 180 degrees, and the fraction of power fed via the latter experiences a phase change of (270 degrees + 90 degrees) = 360 degrees. The two fractions are thus of opposite phase, and the array 3 is not energized. The corresponding fractions fed to the array 4 are, however, in phase. If both phase shifters have the same setting, the array 3 will be energized, but not the array 4. In another embodiment, the commonly controlled sections of the two phase shifters are removed, and a third phase shifter is instead placed in the input to the first hybrid circuit (Fig. 3, not shown). Fig. 4 shows an arrangement in which four radiating elements 13 14, 23, 24, each cover a quadrant in azimuth and are energizable one at a time. A feed system comprises two sets of pairs of hybrid circuits 15, 17 and 25, 27 respectively interconnected via pairs of variable phase shifters 111, 112 and 211, 212. One input terminal of each of the hybrid circuits 15, 25 is connected to one output terminal of a hybrid circuit 5, and their other output terminals are connected to respective matching loads 16, 26. Input power to the feed system is connected through a variable phase shifter 113 to one input terminal of the hybrid circuit 5, the other input terminal of which is connected to a matching load 6. Two other hybrid circuits 9, 10 are provided, the output terminals of which are connected to respective ones of the radiating elements 13, 14, 23, 24 and the input terminals of each of which are connected one to an output terminal of the hybrid circuit 17 and the other to an output terminal of the hybrid circuit 27. If, for example, the radiating element 13 is to be energized, the phase shifters 111, 112, 211, 212 are set, respectively, to 0 degrees, 0 degrees, 90 degrees, 270 degrees. It is possible to use such an arrangement where the various radiating elements are adapted to transmit signals of different frequencies. In another arrangement, (Fig. 5, not shown) feeding systems are provided for use until a circular array of radiating elements of the kind described in Specification 1,171,626. There are four successive sets of elements a 1 to a n , b 1 to b n , c 1 to c n , d 1 to d n , which are grouped in units a 1 , b 1 , c 1 , d 1 &c. A feeding system allows any two adjacent elements of a unit to be energized. Thus, the elements a 1 , c 1 are coupled through one pair of hybrid circuits and variable phase shifters similar to those shown in Fig. 2, and the elements b 1 , d 1 are coupled through another pair. One input terminal of each of the hybrid circuits remote from the elements is connected to an amplitude control system and the other terminal is connected to a matching load. The amplitude control system comprises two hybrid circuits which are interconnected by variable phase shifters.