Improvements in high gain antenna system with low side lobes

摘要

1,108,092. Aerials. SANDERS ASSOCIATES Inc., 26 March, 1965 [26 March, 1964], No. 12855/65. Heading H4A. An aerial array comprises at least two spacedapart, overlapping V-aerials 118, 120, Fig. 12, the legs 126, 128 of the one being parallel, respectively, with the legs 130, 132 of the other, and the bisectors of their apex angles being co-planar, said aerials being fed at their apex 122, 124 from an R.F. source with a phase difference between them determined by their spacing S H so that their radiations combine in a direction lying in the plane of the said bisectors. As described, the apexes 122, 124 of the aerials are higher above the ground than their ends 126a, 128a, and 130a, 142a and the latter are terminated by resistors 134. The spacings S H and S v between the aerials are arranged so that sides lobes produced by the array are minimized and radiation is concentrated in the main lobe. In a second embodiment (Figs. 4, 5, not shown) aerials of tandem-V form are used, in which each V-aerial is connected at its ends to the ends of a second opposite-facing V-aerial. The second V-aerial may be of the same shape as the first V-aerial and be co-planar with it, when a rhombic aerial is formed. As described, an aerial (10) is supported by masts (62) at its apexes and transverse corners and another similar aerial (12) is supported below at a distance Sy by other masts (62), the horizontal separation of the aerials being S H . In a third embodiment, (Figs. 10 and 11, not shown), two tandem-V-aerials (84), (86) are supported on six masts only, common apex masts (108), (110) being used, and in a fourth embodiment (Figs. 14, 15, not shown) two arrays of this kind are combined using a total of eight masts. The terminating resistances may be omitted from the aerials, although they will then usually cease to be uni-directional. The reflectivity of the ground may be enhanced if necessary by installing ground wires. Multiples of the arrays may be used to improve directivity. An array with a feed arrangement such that both horizontally and vertically polarized waves are radiated is described (Fig. 13, not shown) and comprises a transformer (138) having a primary winding (140) and a secondary winding (142) provided with a centre tap 144. The secondary (142) is connected to the aerial and a transmitter (150) for horizontally polarized radiation to the primary (140). A transmitter (154) for vertically polarized radiation is connected to the secondary centre tap (144).