GB1218111A - Klystron - Google Patents

Abstract

1,218,111. Klystrons. PHILIPS ELECTRONIC & ASSOCIATED INDUSTRIES Ltd. 26 Jan., 1968 [31 Jan., 1967], No. 4235/68. Heading H1D. In a klystron in which a pair of drift tubes 5, 6 terminate in a resonant cavity 1 formed by a pair of flanges 2, 3 and a dielectric tube 4 surrounding by an unevacuated cavity, and in which the interaction gap between the ends of the drift tubes is less than one wavelength at the operating frequency, inductive means are arranged around the path of the beam, to increase the characteristic impedance, and thereby permit the use, at a given frequency, of a smaller resonant cavity with the retention of adequate bandwidth. As shown, Fig. 2, two bevelled rings 7, 8 are supported opposite the ends of the drift tubes by conductors 10 which each make a half turn around the cavity axis; alternatively, the rings may be supported by a plurality of axially extending rods (Fig. 1, not shown). In the arrangement of Fig. 4, the bevelled ends of the drift tubes project into the cavity, and a conductor 21 having one end secured to flange 2 and the other left free is wound in one and a half turns around the dielectric tube 4, as shown, or alternatively may be disposed within the evacuated portion 1. In a modification of this arrangement, a plurality of helically wound conductors, surround tube 4, and have their ends secured to movable rings mounted one on each of the flanges, adjustment of the rings to vary the pitch of the helix providing tuning of the cavity (Fig. 5, not shown); or the conductors each describe a loop about an axis which is perpendicular to the cavity axis (Fig. 6, not shown). In further arrangements, a sequence of spaced annular discs, which additionally enhance coaling, are mounted upon the projection bevelled ends of the drift tubes (Fig. 3, not shown); and annular plates which fit around flanges 2 and 3 to form the end-plates of the outer, unevacuated portion of the cavity are provided with a plurality of radially extending arcuate slots (Fig. 7, not shown).