GB1328172A - Antennae - Google Patents

Abstract

1328172 Aerials SONY CORP 19 April 1971 [21 Nov 1970] 25784/71 Heading H4A A wideband aerial comprises a first aerial element formed by a conductive plate member in which a closed loop portion is combined with a dipole portion. The outer ends of the dipole portion are electrically connected to the loop portion, and at least one window is formed between the two portions. The total window area is from 1/8 to 7/8 of the surface area, including said total window area, defined by the outer periphery of said conductive plate member. The aerial further comprises another aerial element, mounted forwardly of the first aerial element. The first aerial element may be a flat circular conductive plate 1, Fig. 1, of diameter I with a window 2 formed by two sector portions 2a, 2b which merge near the centre O of the plate. There results a ring-shaped loop portion of thickness t to which extend sectorshaped dipole arms each of angle #, and having feed points 4a, 4b near the centre of the element. The diameter l may be about one-third of the longest operating wavelength. The thickness t is small compared with l (for example, l/25) and the angle # may be selected according to the operating frequency band and the value of impedance desired (# may be, for example, from 15 degrees to 150 degrees). In other arrangements featuring flat conductive plates, the shape of the window is varied and, in some, the shape of the periphery as well (Figs. 7 to 10, not shown). An element of this kind may be fitted inside a television receiver (Fig. 11, not shown). If an element of this kind is to be used as a reflector the two dipole arms may be merged at the centre, so that two windows are formed (Fig. 12, not shown). Alternatively, the dipole feed points may be connected by an inductor (Fig. 16, not shown). Instead of being flat, the element may be of paraboloidal shape (Fig. 13, not shown). In a first embodiment, such a paraboloidal element is associated as a reflector with a simple dipole active element (Fig. 14, not shown). In other embodiments, Yagi-type aerials comprise reflector elements of the kind described above, associated with conventional directors and with active elements which are either of the kind described above or are of "bow-tie" dipole type (Figs. 17, 18, not shown). In another embodiment, a dipole 101, Fig. 22A, is associated with a paraboloidal reflector element 100 of the kind described above. The dipole 101 has arms which are bent back towards the element 100, and it is fed from the rear of said reflector through, an impedance matching line 10a. A hinge 10b allows the line with the dipole to be folded upwards for transit, when a slidable support 17 has been released (Fig. 22B, not shown). The element 100 is supported from a mast 20, mounted on a base 19, by an arm 21.