GB764012A - Improvements in or relating to travelling wave tubes - Google Patents

Abstract

764,012. Travelling-wave tubes. WESTERN ELECTRIC CO., Inc. Oct. 15, 1954 [Oct. 16, 1953], No. 29758/54. Class 39(1). A travelling-wave amplifier operating on spatial harmonics of the transverse electric circular mode has a slow-wave circuit consisting of a succession of groups 11, Fig. 1, of conductive members, each group containing a plurality of coplanar members 13 which dissect the circular electric field lines into separate portions. As shown the wave guide consists of a stack of plates 12 each pierced with an aperture containing a number preferably odd, of sectors 13 joining to the edge by thin stems 14. The electron beams are fired either through the gaps 15 or through holes or channels in the sectors 13, and the thickness t and spacing d are chosen as explained in Specification 714,832 to give spatial harmonic operation ; for a oneinch diameter aperture, t = 0À075 in., d = 0À034 in. and 1200 volt electrons are synchronized at 9000 Mc. The entrance apertures may be graded from simple vanes as shown on the right, for impedance matching. Other forms of apertures may be simple vanes 41, 43, Fig. 4, staggered in successive plates and acting on an annular beam 44 ; or the staggered vanes 34, 35, Fig. 3, may carry wire loops 31 interdigitated as shown to enclose a number of beams 36. Alternate plates may be given a voltage difference to effect electrostatic focussing. Backward-wave operation may be employed.