GB609712A - Electron discharge devices - Google Patents

Abstract

609,712. Electron discharge devices. MARCONI'S WIRELESS TELEGRAPH CO., Ltd. Aug. 23, 1944, No. 16107. Convention date, Nov. 14, 1942. [Class 39 (i)] An electron discharge device of the magnetron type includes an elongated cathode situated coaxially in a cylindrical chamber, the wall of which is constituted by a plurality of anode segments so formed from a conducting member as to provide resonant cavities between said segments, and conducting loops positioned just above the cavities, said loops lying in planes passing symmetrically and radially through the resonant cavity circuits and acting to suppress undesirable modes of oscillation. In the construction shown in Figs. 1, 2 and 4, an elongated cathode 10 of the indirectly heated type is surrounded by a cylindrical anode block 11 of conducting material, preferably copper, formed with a plurality of anode segments 15 and cylindrical resonant cavities 13 connected by radial slots 14 with the cylindrical space 12 surrounding the cathode. A permanent U- shaped magnet 30 provides a magnetic field in the direction of the cathode. Radiating fins 29 are secured to the anode block 11. The anode block 11 is provided at each end with a cup-shaped depression 16 and the outer end of each depression is closed by a disc-shaped conductive cover member 18 which may be brazed or soldered to the anode block with a vacuum-tight seal. Closed conducting loops 33 are secured to the top and bottom closure members 18 so as to lie adjacent the cavities 13 in planes passing radially and longitudinally through the cathode 10. The loops 33 may be secured to the walls of the cup-shaped depressions 16 or to the walls and to the bottoms of the cup-shaped depressions 16. The cathode 10 is supported within the anode block by leads and support wires 10<11> electrically connected to collars 10<1>. Electron shields 20 are supported from these leads. The support wires 10<11> form extensions of the inner conductors of coaxial cables, the outer tubular members 22 of which are sealed by means of the cup-shaped seals 24. If desired, tuning members can be secured to the members 10<11> and 22 for tuning the cathode leads to prevent radio-frequency currents being directed into these leads. A coupling loop 26 is positioned within one of the cavities 13 for extracting energy from the magnetron, the loop being connected to a lead 26<1> forming the internal conductor of a coaxial cable, the outer conductor 27 of which is provided with a threaded portion which can be secured to the outer conductor of a coaxial cable. The conductors 26<1> and 27 are sealedoff by the cup-shaped member 28.