GB953488A - Improvements in slow-wave structures for travelling wave tubes - Google Patents

Abstract

953,488. Travelling-wave tubes. SIEMENS & HALSKE A.G. June 12, 1962 [June 12, 1961], No. 22443/62. Heading H1D. A slow-wave structure for a travelling - wave tube includes a plurality of plates stacked together and comprises a central hollow conductive waveguide 1 and a hollow coupling conductor 2 extending parallel thereto, where the coupling waveguide is constituted by a series of coincident apertures, one of which lies in each of the stacked plates, wherein the central waveguide is constituted by a series of further apertures one of which lies in each of the stacked plates, wherein alternate plates include projections 7 extending across the further aperture over the axis of the structure and each of which includes a central aperture 8 lying on the axis, wherein adjacent projections extend from opposite sides of the central waveguide to form an interdigital delay-line, wherein a longitudinal bar 3 extends into the coupling conductor from one end of the structure and is conductively connected to both a wall of the coupling conductor remote from the axis and to a metal plate 4 which extends over, and lies perpendicular to, the axis, wherein the metal plate is disposed in a further waveguide section 5, and is provided with an aperture 6 in line with the central aperture, and wherein the spacing between the metal plate and the adjacent one of the stacked plates 7 is smaller in the region of the axis than in that region in which the stacked plate bounds the central waveguide. The cross-section of the coupling waveguide may be rectangular, and the diameter of the aperture 6 in the metal plate 4 is preferably smaller than the diameter of the central apertures 8.