GB1366579A - Antenna - Google Patents

Abstract

1366579 Aerials MINI-PRODUCTS Inc 27 June 1972 [30 June 1971] 29973/72 Heading H4A An aerial comprises a radiator consisting of a single loop of wire, the total distance round the loop being approximately one wave length at a predetermined frequency, loading units mounted 180 degrees apart at the high voltage points at said frequency of said radiator, and being connected thereto, said loading units each comprising a series connected inductor and a loading capacitative element, said inductor acting as an R.F. choke at said frequency, and said inductor and said loading capacitative element acting as an additional electrical length to said radiator at a lower frequency than said predetermined frequency, thus providing operation at two different frequencies. As described, a four-band loop aerial has a single wire radiator 11, Fig. 1 of diamond shape which is fastened to the four ends 12, 13, 14, 15 of supporting cross members 40, 41 made of insulating material. Multiband loading units 16, 17, 18 are mounted at the end 14 of the cross member 41, and similar units 19, 20, 21 are mounted at the opposite end 12. A feeder terminal board 24 is mounted at the end 15 of the cross member 40. Metal sleeves 25, Fig. 1a, at the ends 12, 14 each provide support both for the wire radiator 11 and for a tubular coil former 19<SP>1</SP> made of insulating material, upon which are wound inductors 36, 37, 38, and which supports three capacitor elements each consisting of a ring 31 and spokes 43. Said capacitor elements are located at the outer ends of respective inductors, and are connected thereto. The inner end of the inductor 36 is connected to the sleeve 25 and the inner ends of the other inductors may also be connected thereto, so that the three loading units are in parallel. Alternatively, the three loading units may be connected in series, or the inner two may be in series, with the third in parallel. In other embodiments, the loop aerial is of circular or elliptical shape (Figs. 2, 3, not shown). An active aerial of this kind may be associated with a parallel spaced apart passive aerial of the same kind, the latter acting as a reflector (Fig. 6, not shown).