GB540842A - Transmission systems for high frequency electro-magnetic waves - Google Patents

Abstract

540,842. Electron-oscillators. STANDARD TELEPHONES & CABLES, Ltd. May 24, 1940, No. 9182. Convention date, May 26, 1939. [Class 39 (i)] Vacuum tube for ultra-high frequencies comprises a tube 33, Fig. 5, with an inner conducting surface whose axial length is comparable with or greater than the operating wave-length, an electron emissive filament 35 stretched diametrically across the tube, and a magnetic field, represented by poles 41, 42, whose lines of force are parallel to the filament. Instead of the filament, a stream of electrons projected from a gun system on one side of the tube and collected by an anode on the other side may be used. The tube is open at one or both ends, and the open ends are coupled to di-electric guides. The setup shown in the Figure is for repetition between guides 29, 30, which are sealed to the envelope 20 by insulating tubes 24, 25, provided with internal conducting layers 26 and transverse dielectric partitions 27. The tube is free to expand and contract axially while being kept in position by its ends which are slotted to avoid transverse stresses. The tube is at a given positive potential relative to the filament and the electrons describe helical paths about the lines of force of the magnetic field, and the frequency of rotation of the electrons is synchronized with the frequency of the incoming signals, and one of the resonances of the tube. Other arrangements are described in which the tube is used for receiving or transmitting oscillations. The filament is carried by resilient arms 36 secured to rigid rods 37 supported in a metal plate 39 in the envelope and connected to the leads 38. In the arrangement shown in Fig. 7, a stream of electrons 63 generated by a spiral filament 71 and anode 73 passes through an opening 62 on one side of the tuned cylinder 61 and is collected on a plug 64 diametrically opposite.