GB1272990A - Directional antennae - Google Patents

Abstract

1,272,990. Aerials. SONY CORP. 10 Sept., 1969 [10 Sept., 1968; 14 Dec., 1968], No. 44682/69. Heading H4A. An aerial comprises a loop aerial element consisting of at least three arcuate conductive members. Output terminals are provided on the adjacent ends of two of the members, and impedance means having values which satisfy stated mathematical relationships are connected between other adjacent ends of the said members. In one embodiment, two upper and lower loops are respectively made up of members 29, 30, 31, 32 and 33, 34, 35, Fig. 15, and said loops are spaced apart by conductive bars 41, 42, 43, 44. Feeder terminals 18 are provided on the adjacent ends of the members 29, 32 and a dummy load Z 3 is connected between the adjacent ends of the members 30, 31. Air gaps between the adjacent ends of the pairs of members 29, 30; 31, 32; 33, 34; 34, 35 provide capacitive impedances and two telescopic dipole arms 46, operating at a lower frequency than the loop element, are connected through trap circuits 47 to the ends of the members 29, 32 which are remote from the terminals 18. The dipole arms may alternatively be connected through trap circuits to the feeder terminals (18), Fig. 18A (not shown), or to the bars (41), (42) Fig. 18B (not shown). In another arrangement the dipole arms are connected to shortcircuited ends of quarter-wave lines (the wavelength (#) being that corresponding to the midband frequency of operation of the loop element). The other ends of said lines are respectively connected to the adjacent ends of the members (33), (34) and (34), (35), Fig. 18D (not shown). The dipole arms may alternatively be connected to the junctions of two pairs of #/4 lines, one pair being open-circuited, and the other pair being connected to the feeder terminals (18), Fig. 18E (not shown). Two pairs of dipole arms may be provided, each arm being connected through a trap circuit to an end remote from the feeder terminals of one of the members (29), (32), (33), (35), Fig. 18C (not shown). The arrangement as shown in Fig. 15 may be used without dipole arms being provided (Figs. 12, not shown), and in another embodiment four arcuate sheet members are used, each having an outline as defined, for example, by the members 32, 35 of Fig. 15 and the vertical lines joining their ends (Fig. 11, not shown). Three impedance elements are provided, respectively connected across gaps between the members. In other embodiments, members forming single loops are used. Adjacent ends of members may be bridged, for example, by inductors (Fig. 7, not shown) or by active elements (Fig. 9, not shown). It is stated that suitable selection of the impedance elements reduces sidelobes and increases operating bandwidth. Specification 1,250,562 is mentioned.