GB592929A - Improvements in or relating to magnetron apparatus for producing high frequency electrical oscillations - Google Patents

Abstract

592,929. Magnetrons; frequency modulation. WESTERN ELECTRIC CO., Inc. Aug. 12, 1943,_No. 13106. Convention date, May 1, 1942. [Classes 39 (i) and 40 (v)] In a magnetron of the type in which the anode surfaces 18 are backed by a number of resonant cavities 14, Fig. 1, coupled together by end-spaces 26, 28, tuning is effected by moving a conductor, such as an end-plate 36, 38, within the end-space so as to vary the magnetic or electric coupling between the resonators. A screw 58 may be used to effect permanent adjustment of the end plates which have flexible edge connections 40, or a moving coil 64 in conjunction with permanent magnet 68 may modulate the frequency in accordance with signals. The leads 22 to the cathode 20 are brought out across the mid-plane of a resonator so as to minimize coupling between the leads and the resonator field ; energy is taken off by loop and coaxial line 48. The discharge space is closed by discs 32. The effect of moving the end-plate, which, operates mainly by varying the cross-section of the magnetic flux 56 coupling adjacent resonators, may be enhanced by attaching to it curtains of metal which hang down nearly to the block face between alternate resonators. In a modification which acts more upon the electric coupling between adjacent faces of the anode slots 16, an annulus 74, Fig. 4, may be moved axially by rod 76 and flexible joint 78 toward or away from the region of the slots 16. The annulus may be slit as shown to allow it to pass the lead 22 and is connected at 80 to the anode block. The whole device may be enclosed in an evacuated vessel. The cathode may be self-heated during operation.