GB595352A - Improvements in or relating to electric wave guides - Google Patents

Abstract

595,352. Wave-guides. CORK, E. C., and MANIFOLD, M. BOWMAN-. Sept. 1, 1942, No. 12349. [Class 40(v)] Leakage at a gap in a wave-guide where two sections are mounted for relative rotational movement is prevented by providing flanges or overlapping surfaces at the gap of such dimensions as to provide a short circuit for waves travelling along the guide, but to form a blocking circuit for waves emerging through the gap. As shown in Fig. 1, the fixed guide 7 and the rotary guide 6 are each provided with a flange 8, 9, the radial length of which is a quarter wavelength, the flanges being slightly spaced from each other. The flanges may be an odd number of quarter-waves in radial length, and the gap between them may be widened for the intermediate quarter wavelengths so as to produce reflections by their different characteristic impedances and so reduce the leakage still further (Fig. 3, not shown). The gap may be of labyrinth form, Fig. 2, the sections X having a larger gap width than the sections Y. Instead of flanging the guides, one may be enlarged in diameter for a quarter-wave of its length and may enclose the other so that the gap is of cylindrical form. The rotatable portion 12, Fig. 5, of the guide may have a wave-radiating slot 13 situated at the focus of a parabolic reflector 14 which rotates with the guide. A second reflector 17 and slotted wave-guide 15 may be rotated jointly with the first and may transfer received energy to a stationary wave-guide 19 leading to the receiver.