GB1011305A - Improvements in or relating to antenna arrays - Google Patents

Abstract

1,011,305. Aerials. SIEMENS & HALSKE A.G. Nov. 23, 1962 [Nov. 23, 1961], No. 23632/65. Divided out of 1,011,303. Heading H4A. Means are described for modifying a known aerial array, Fig. 1, comprising four half-wave dipole assemblies 2 and 3 (the other two not being shown), fed with signals from a common source via individual feeders such that at a certain frequency the phase of the energy reaching the dipole assemblies advances by 90 degrees from one assembly to the next, whereby the aerial can operate over a frequency range of 0À85 to 1À15 fm, where fm is the geometric mean frequency, without the minimum radiated energy in the horizontal plane falling below half the maximum value. In the arrangement of Fig. 3 dipole assembly 75 is fed with a feed line #m/4 shorter than that feeding assembly 74, dipole assembly 76 is fed with a feed line the same length as that feeding assembly 74, but with the addition of a phase reversing unit, and dipole assembly 77 is fed with a feed line the same length as that feeding assembly 75, but with the addition of a phase reversing unit. The dipole assemblies comprise shortened full-wave dipoles with a fineness ratio of 15, and spaced a distance 0À28 #m in front of their associated reflectors. Each assembly is shifted along their respective tower side such that along a diagonal direction H, Fig. 2, the radiation centre 67 of one assembly leads the radiation centre 66 of the adjacent assembly by a distance d = 0À77-,#m/4 rather than the normal #m/4 distances. The resulting horizontal lobe diagrams f = 0À85 fm, f = fm, f = 1À15 fm are shown at 78, 79 and 80, respectively.