GB771532A - Improvements in or relating to aerials - Google Patents

Abstract

771,532. Radio aerials. MARCONI'S WIRELESS TELEGRAPH CO., Ltd. July 29, 1954 [Aug. 21, 1953], No. 23166/53 Class 40(7) An aerial system, Fig. 1, comprises first and second aerial elements 1, 2, the first element being situated at the focus of the second element and having an aperture much larger in one direction than the other, and the elements being such that the beam from element 1 is projected on to element 2 and has dimensions thereat substantially equal to those of element but with the shorter dimension of the beam less than that the larger dimension of element 1. The aerial elements may comprise lenses, lens 1 being a shielded lens at the end of a beam 3 as shown, or mirrors. Thus Fig 2 (not shown) illustrates an arrangement in which element 1 is a cheese-type unit facing into but offset from the reflection path of a cylindroparabolic mirror forming the second element. In place of the "cheese," other elements such as the "pill-box" or "foghorn," may be used. The aerial system has application as a wide-angle vertical scanner, this being effected by reciprocating element 1 up and down as indicated by the double headed arrows. Alternatively, a plurality lenses 1 may be stacked over above the others and switched in succession. Two separate elements 1 closely superimposed one above the other may be employed for a precision height finder using the "split" technique, Fig. 3 (not shown). Fig. 4 illustrates a modification arranged for azimuth scanning, element 2 being replaced by a ring lens 22 of section corresponding to element 2.