GB657487A - Improvements in and relating to magnetrons - Google Patents

Abstract

657,487. Magnetrons. BRITISH THOMSON-HOUSTON CO., Ltd. Sept. 15, 1947, No. 25219. Convention date, June 23, 1945. [Class 39 (i)] A magnetron comprises a parallel conductor transmission line 5, 6, Fig. 1, extending through the envelope 1 and terminated inside the envelope 1 by a loop 2, two anode segments 9, 10, are connected to different conductors of the line and a third anode segment 14 is connected to the loop 2 at a neutral point. The transmission line 5, 6, preferably of copper, is sealed through fernico sleeves 3, 4 and is provided with a movable short-circuiting conductor 8 outside the envelope 1, for tuning. A cathode 18 of tungsten wire is carried from rigid leads 20 by resilient members 19, and shields 22 are mounted at either end of the anode segments on the members 19 to protect the glass envelope wall from electron bombardment. A further shield 24 is attached to anode segment 9, and a getter 25 is provided. " Neutrode " 14 subtends 180 degrees and segments 9, 10, 90 degrees each at the cathode. The D.C. anode terminal is connected at 27, and the magnetic field is produced by a permanent or electromagnet (not shown). The distance between short-circuiting member 8 and anode segments 9, 10 is a half wavelength or any multiple of a half wavelength. In a modification, Fig. 3, the anode segments 28, 29 have end portions 30, 31 projecting radially towards the cathode and each subtending angles of 51.4 degrees thereat. A shield 34 is provided, similar to shield 24 in Fig. 1. In a further modification, Fig. 5, anode segments 35, 36 are L-shaped and each subtend 60 degrees at the cathode. In a further modification, Fig. 7, segments 41, 44 are both " neutrodes " and are connected together by two conductive annuli 45. The cathode 47 has an extension integral therewith connected to a support similar to 19, Fig. 1. Segments 39, 40 arranged between the two " neutrodes " each subtend 36 degrees at the cathode. The Specification as open to inspection under Sect. 91 states that in the form of Figs. 7 and 8, the cathode is located in a recess in a cylindrical member concentric with the anode segments. In all forms the transmission line and anode segments may if desired be formed from a single conducting block though the built-up structures illustrated are preferred. The mode of operation of the devices is compared with that of multi-resonator magnetrons with specified numbers of interaction gaps. This subjectmatter does not appear in the Specification as accepted.