GB1011303A - Improvements in or relating to antenna arrays - Google Patents

Abstract

1,011,303. Aerials. SIEMENS & HALSKE. Nov. 23, 1962 [Nov. 23, 1961], No. 44328/62. Heading H4A. Means are described of modifying a known aerial array, Fig. 1, comprising four half-wave dipole assemblies 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 fm 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 52 is fed with a feed line #m/4 shorter than that feeding dipole assembly 51, dipole assembly 53 is fed with a feed line the same length as that feeding assembly 51, but with the addition of a phase reversing unit, and dipole assembly 54 is fed with a feed line the same length as that feeding assembly 52, but with the addition of a phase reversing unit. By this arrangement, the phase difference between the energies at dipole asemblies 51 and 52, and between dipole assemblies 53 and 54, increases with increasing frequency, whilst that between dipole assemblies 52 and 53, and between dipole assemblies 54 and 51, decreases with increasing frequency. The four dipole assemblies are staggered along the side of the tower such that d<SP>1</SP>/d<SP>2</SP> = 1À15, and dipole assemblies 51 and 53 are turned through an angle α. The resulting horizontal lobe diagrams for f=fm, f = 85fm and f = 1.15fm are as shown at 60, 59 and 61, respectively. Alternatively, Fig. 2 (not shown), distance d 1 can be left equal to distance d 2 . Specification 1,011,304 is referred to.