GB841804A - Antenna - Google Patents

Abstract

841,804. Aerials. STANDARD TELEPHONES & CABLES Ltd. Oct. 31, 1958 [Nov. 1, 1957], No. 34998/58. Class 40(7). An aerial system for the transmission or reception of radio energy in two separated frequency bands utilizes energies of orthogonal plane polarizations and is arranged so that in design the radiation patterns for the two frequency bands may be determined independently. The system consists of a first waveguide 1 dimensioned for the transmission of a first wave energy and having a flaired mouth within which lies a second waveguide 2 for the second wave energy of a polarization perpendicular to that of the first. The second waveguide is coextensive with a portion of the first and in a substantially non- interferring relationship with energy propagated in the first. Its mouth is independently flaired. In the embodiment shown the first waveguide consists of a rectangular guide 3 leading to a mouth opening through a part having flared top and bottom walls 4 which control the radiation pattern of the vertically polarized energy propagated along it. The second waveguide is formed by the top and bottom walls of waveguide 3 extended through the flared portion by spaced rods 9 and side walls consisting of the limits of horizontal fins 5, 6, attached to the side walls of the guide 3. As shown these fins are shaped so that waveguide 2 is led out of waveguide 1 to separate translating means 12. It is explained with reference to Figs 4, 5 and 6 (all not shown) that the waveguide 2 may alternatively extend along the full length of waveguide 1 to translating means and the waveguide 1 be fed by a centrally mounted vertical probe at a suitable distance from the end of the guide. The edges of the fins 6 and 7 are flared out at the radiating end of the guide 10 to determine the radiation pattern of the system for horizontally polarized waves.