GB953805A - Improvements in or relating to directional aerial systems - Google Patents

Abstract

953,805. Aerials. MARCONI CO, Ltd. Sept: 26, 1961 [March 29, 1961], No. 11499/61. Heading H4A. An aerial system comprises a plurality of linearly disposed conductor pairs of progressively differing lengths, each pair being composed of equal length conductors connected together at one end and being close to each other, the ratio of the electrical length of each conductor pair to that of the next, shorter, pair being constant throughout the system, and a plurality of collinear series-connected connectors each connecting the free end of one conductor of a pair to the free end of a conductor of the next pair of shorter length, the ratio of the electrical length of each conductor pair to that of the connector connecting it to the next shorter pair being constant throughout the system. One embodiment, Fig. 1, comprises a plurality of conductor pairs P1 to P11 each consisting of a pair of closely spaced conductors 1 and 2 connected together at their upper end, the pairs being supported parallel to each other by a stay S from a mast M. These are connected in series by collinear connectors C2 to C11 and the ratio of the electrical length of each pair to that of the connector connecting it to the next, shorter, pair is made constant throughout the system, and the lengths of the pairs increase logarithmically from the shortest P1 to the longest P11. The dimensions are such that one conductor pair is, at one frequency of the bandwidth of the aerial, a quarter of a wavelength long and is spaced from its shorter neighbour by one quarter to one twentieth of that wavelength. The connectors C2 to C11 may be the central conductor of a coaxial feeder, Fig. 1a, and further embodiments form balanced aerials. Yagi arrays of directors may be used with the system as, for example, with an embodiment producing circularly polarized radiation, Fig. 7. Reference has been directed by the Comptroller to Specification 884,889.