GB927051A - Improvements in or relating to antennas for high frequencies - Google Patents

Abstract

927,051. Aerials. R. GUERTLER. Sept. 28, 1960 [Oct. 7, 1959], No. 33323/60. Class 40 (7). An aerial is formed of a plurality of dipoles of various lengths which are connected at their centres and their ends to form a meandering conductor. Figs. 1 and 3 illustrate examples of such aerials. The aerial is fed at A, B and operates over one or more wide frequency bands. If A, B are shorted, the invention acts as a reflector. In one embodiment, Fig. 4, dipoles 5, 6 and 7, 8 are of equal length, three times that of dipoles 1, 2 and 3, 4. The dipoles are interconnected as shown. At a frequency 3f at which the dipole 1, 2 is a half wavelength, dipoles 1, 2 and 3, 4 act as a folded half-wave dipole and dipoles 5, 6 and 7, 8 as a folded three half-wave dipole. At frequency f, the long dipoles act as one folded half-wave dipole and the short dipoles act as stubs, loading the aerial inductively at the feed-point. The spacing of the dipoles is about one-tenth of a wavelength at the highest operating frequency. Rod or screen reflectors are used to increase gain and directivity, these factors are also increased by using two aerials, Figs. 9 and 10 (not shown). The reflector elements may each be divided by means of insulators into a number of parts, each a half-wave long at the highest frequency used. The capacitance that is introduced by the aerial mounting arrangements may be reduced by placing a conductor to join the centre points of rods 13, 24, Fig. 4. The conductor may be insulated therefrom.