GB1004049A - Improvements in or relating to antenna arrangements - Google Patents

Abstract

1,004,049. Aerials. SIEMENS & HALSKE A.G. Sept. 3, 1963 [Sept. 4, 1962], No. 34708/63. Heading H4A. A wide-band aerial comprises (1) a primary radiator in the form of a surface of revolution fed from one end such that the distance along the axis of revolution from the feed point to the effective emission area of the radiator decreases with increasing frequency and (2) a fixed reflector system such that the distance from the axis to the most effective reflecting part of the reflector system decreases correspondingly with increasing frequency. In one embodiment the primary radiator 1 is in the form of an ovoid having a vertical axis of symmetry surrounded by an oblique angled cone and merging at its base with the inner conductor of a coaxial feeder 4, the outer conductor of which connects with a ground plane 2 which may be raised, 3, in the vicinity of the base to improve the radiation pattern at higher frequencies. Three thick barlike reflectors 5, 6, 7, of decreasing height are provided at different distances from the axis of the radiator to form the reflector system and it is stated that for such a radiator the distance from the feed point along the axis of the radiator to the effective emission area decreases with increasing frequency so that in turn the reflectors 5, 6 and 7, become effective. In another embodiment two such radiators are used as a centre fed dipole and these, together with dipole reflectors are disposed at the focus of a parabolic reflector, Fig. 4 (not shown). In other embodiments each reflector of the reflector system may take the form of two planes intersecting in a line parallel to the axis of the radiator, Fig. 3 (not shown), and an array of parallel radiators employing such reflectors, Fig. 5 (not shown); alternatively the reflectors may be curved in one plane. The arrangement shown in Fig. 1 is stated to be effective over a five to one frequency band.