Feeds for transmission lines

TLDR: In this article, the authors proposed a novel way of supplying the energy to each joint conductor, where there is employed a conductive feed ring (or short tube) positioned around and spaced from the conductor, and this ring is itself fed by a stub and is shorted to the relevant outer joint conductor at a point diametrically opposite the stub.

Abstract: It is often desired to transfer microwave energy into a coaxial cable transmission line in circularly symmetric (Transverse Electromagnetic) mode One case is in low power radar systems, wherein rotating joints are employed in the transfer of microwave electromagnetic radiation energy between two sections of apparatus one of which rotates relative to the other The well-known "stub-supported" fashion is one way of feeding the joint, but it is not problem-free, and necessitates a significant length of conductor between the two stubs, which means that such joints are considerably longer than is desirable The invention provides a novel way of supplying the energy to each joint conductor, where there is employed a conductive feed ring (or short tube) positioned around and spaced from the conductor, and this ring is itself fed by a stub and is shorted to the relevant outer joint conductor at a point diametrically opposite the stub