GB712565A - Improvements in or relating to travelling wave magnetron tubes - Google Patents

Abstract

712,565. Travelling-wave tubes; magnetrons. COMPAGNIE GENERALE DE TELEGRAPHIE SANS FIL. July 7, 1952 [July 30, 1951], No. 17079/52. Class 39(1) In a travelling-wave tube in which an electromagnetic wave injected into a delay line is amplified by interaction with an electron beam moving parallel to the line and perpendicularly to crossed electric and magnetic fields, at a velocity equal to the ratio of these two fields and to the phase velocity of the wave, the delay line is divided into two sections each co-operating with an opposing electrode to form two interaction spaces providing contrary energy exchange mechanisms; the first space provides strong focusing of the electrons and the second amplification of the wave. The first delay line section 9, Fig. 4, is at a negative potential and is in alignment with the negative electrode 6 of the second interaction space. It is opposed by a positive electrode 8 in alignment with the second delay line section 10. This section 10 is at a positive potential and is situated opposite the negative electrode 6. As shown in Fig. 4, the positive electrode 8 forms an attenuating section for the second delay line section 10. The first interaction space is relatively short; so as not to excite a predominating electron de-focusing wave. By using for the focusing section 9 a delay line propagating a wave in the opposite direction to the beam such as a symmetrical interdigitated line or a zig-zag line. an artificial attenuating section need not be provided. The tube of Fig. 5 is arranged to function as a self-oscillator controlled by the wave introduced at 4 by providing an interdigitated or zig-zag line for the amplifier section 10, with the provision of an attenuating section 8 at the end of section 10 adjacent the collector 7, and with the output derived at the opposite end 5. Either tube may'be designed to function as a frequency multiplier by making the beam velocity in the first interaction space equal to the phase velocity of the fundamental wave on section 9, and equal to the phase velocity of the desired harmonic wave on section 10.