Patent GB-483839-A (GB)
Title: Improvements in or relating to magnetron electron discharge devices and arrangementsincorporating the same
IPC: H01J25/52
Filed: 1936-11-05
Abstract: 483,839. Magnetrons and circuits therefor; electric resonators. TELEFUNKEN GES. FUR DRAHTLOSE TELEGRAPHIE. Nov. 5, 1936, No. 30165. Convention date, Nov. 5, 1935. [Classes 39 (i.), 40 (iii),and 40 (v)] A magnetron has a split anode system comprising a plurality of anodes A1 ... A4; Fig. 3, a tuned oscillatory circuit coupled to the anode system, the anodes surrounding the cathode K and contributing to oscillation generation, and a further electrode N surrounding the anodes and the cathode and maintained at a greater positive potential than the anodes so as to serve as an interception electrode to receive electrons which pass the anodes while itself remaining electrically neutral as regards oscillation frequencies. The anodes are thus free to generate oscillations without undue heating by collected electrons. The typical election path is shown in Fig. 3. The electrode N may be split up into a number of electrically connected segments, each facing a gap between the anodes. The electrode may be provided with cooling fins or artificial gas or liquid cooling; it may then form part of the envelope, being closed at each end by ceramic members supporting and spacing the internal electrodes. In a modification the interception electrode is divided peripherally into two segments N1, N2, Fig. 5, between which modulation potentials are applied from a transformer M; the segments are short circuited for oscillation frequencies by condensers Ch inside or outside the tube. H is a resonant circuit. The division mav be axial instead of peripheral. The condensers Ch may be replaced by two capacity plates covering the gaps between N1 and N2 and connected to a higher positive potential than the interception electrodes. In a further modification, the interception electrode system comprises four perforated segments N1... N4, Fig. 9, which are backed by a further electron retarding electrode N0 at a less positive potential. The electrodes N1 ... N4 are connected alternately to a modulating circuit. A battery B introduces a difference of potential between the two pairs of segments to avoid frequency doubling. The perforated electrodes may be composed of wires parallel to the cathode. Fig. 10a shows a magnetron which is integral with a resonator consisting of two hollow metal bodies, preferably hemispheres, coupled together capacitatively by flanges Cu between which pass the leads to the two halves of a perforated double anode system A1, A2. The two halves of the interception electrode system N1, N2 are connected together and to the nodes P<1>, P<11>. The leads to the cathode are brought out through one node. The oscillation anodes may be made as segments of ellipses in order to follow more closely the paths of the electrons. The anodes may also be coated with secondary-electron-emitting material ; by this means electrons arriving in the wrong phase and striking the anodes release an excess of secondary electrons and contribute usefully to oscillation generation. Specification 460,689 is referred to. The Specification. as open to inspection under Sect. 91 refers to electron-discharge devices other than magnetrons and describes a modification in which modulating plates are disposed within a perforated double anode system, on either side of the cathode. This subject-matter does not appear in the Specification as accepted.