GB1305480A - - Google Patents

Abstract

1305480 Aerials; radio direction-finders SIEMENS AG 21 Dec 1970 [23 Dec 1969 (2)] 60457/70 Headings H4A and H4D In an n-dimensional aerial array (n=1, or 2, or 3) each element is associated with a respective phase-shift device, which is continuously variable proportionally to a controlling D.C. voltage. For each dimension there is provided a chain of resistors having values proportional to the spacings between the elements, and fed by a regulating D.C. voltage. The controlling D.C. voltage for a phase-shift device is derived by tapping along the chains at points corresponding to the spatial co-ordinates of its associated aerial element. As described, a three-dimensional array G, Fig. 1, comprises elements such as A whose positions are defined with respect to co-ordinate axes x, y, and which are associated with individual continuously variable D.C. voltage controlled phase shifters, for example helical ferrite delay lines. Control voltages are obtained from three chains of resistors, each fed by an independent direct voltage V 1 or V 2 or V 3 , Fig. 2. The values of the resistors are proportional to the spacings between the aerial elements along the x or y or z axis. Thus considering the element A, voltages V 1A , V 2A , V 3A are tapped along the x, y, z chains respectively, and a control voltage V A is obtained by summing. The co-ordinate axes need not be orthogonal, nor need the spacings between elements be the same, for example, said elements may be arranged along co-planar curves as shown in Fig. 6. In other embodiments planar arrays comprise parallel rows of elements. Two sets of rows may be arranged in orthogonal directions, or three sets of rows may be arranged in directions which are at 120 degrees to each other. The elements are energized so that narrow beams are produced which fan out along the rows. These beams may be swung broadside to their respective rows, and an equivalent pencil beam may be obtained at the intersection of two beams. A jamming station will normally affect one beam only, and the other beam or beams will remain free of interference. In one arrangement of this kind, two mutually perpendicular rows of elements A 1 , A 2 and A 3 , A 4 are provided (Fig. 8(a), not shown). As shown in Fig. 8(b), the aerial elements and the phase shifters are contained in a unit 10. The component arrays corresponding to rows A 1 , A 2 and A 3 , A 4 are marked 11, 12 respectively with corresponding phase shifters 11a, 12a (shown separately for convenience). Phase discriminators 11b, 12b receive outputs from the rows A 1 , A 2 and A 3 , A 4 respectively. A low frequency generator 13 produces control voltages for the phase shifters 11a, 12b, which are taken through switches 14, 15. The resultant phase changes cause the mutually perpendicular fab-shaped beams and/orl the pencil beam at their intersection to swing. When a radiating source is detected the swinging is stopped by the operation of the switches 14, 15 and tracking is continued under control of signals from the phase discriminators 11b, 12b. the aerial arrangement 10 supplies a threshold analyser 16 and a receiver 17. In the device 16, decoding arrangements may be provided for recognizing responding relay stations. A similar arrangement is described in which each component array has virtually four rows of elements, although the central two rows are combined, so that there are actually three rows (Figs. 9a, 9b, not shown). Embodiments in which the elements are arranged to provide rows in three directions at 120 degrees to each other are described with reference to Figs. 10a, 10b, 11, 12 (not shown). Monopulse type operation may also be effected (Figs. 13a, 13b, 13c, 14, not shown).