GB691139A - Improvements in or relating to magnetron oscillators - Google Patents

Abstract

691,139. Magnetrons. ENGLISH ELECTRIC VALVE CO., Ltd. Nov. 9, 1951 [Jan. 8, 1951]. No. 542/51. Class 39(i). A magnetron comprises a cathode 24 coaxially surrounding an anode system consisting of a ring of anode segments 1, 4, 6 surrounding a central resonant cavity and defining resonant cavities, all the cavities being open towards the cathode and alternate cavities opening into the central resonant cavity; the central cavity, which is bounded by upper and lower plates 17, 18 in Fig. 2, is designed to support an H 011 wave which is excited by the anode segments oscillating in the # mode. Refering to Figs. 1 and 2, oscillation at higher modes, such as the H 111 or H 211 , may be prevented by coupling the anode segments by loops 20 to resistive loads 19; for the H 011 mode the coupling is very small so that the resistances cause negligible damping. The output may be taken from the central cavity by a coupling loop and a concentric line, or through an iris 21, which may be adjustable, to a waveguide 22 and window 23. The cathode 24 may be provided with heaters 25 and cooling fins 26. In the modification shown in Figs. 3 and 4 damping of the higher modes is achieved by coupling the central cavity through an annular slot 27 to a resistive load comprising radial slots 28 cut in a cylinder 29 of resistive material. An axially adjustable tuning plunger or disc may be provided in the central cavity or the magnetron may be tuned by projecting one or more clouds of electron space charge into the central cavity.