| 摘要 |
922,821. Velocity modulated tubes. SIEMENS & HALSKE A.G. April 28, 1961 [April 29, 1960], No. 15452/61. Class 39 (1). A beam-type parametric amplifier comprises an electron gun 1 and a collector 7 having between them a first waveguide 4 extending perpendicularly to the electron beam 3, a second waveguide 6 perpendicular to the beam, and a drift tube 8 electrically insulated from and disposed within the second waveguide 6 so that the electron beam passes through coincident apertures disposed centrally in each of the waveguides. In operation, the electron beam is velocity modulated by a pump signal travelling in the direction 5 along conductor 4, and is then reactively coupled to a wave to be amplified travelling in direction 11 along conductor 6. The electron beam is preferably rectangular, a ferrite block 12 may be provided on one wall of the waveguide 6 to attenuate reflected waves, and the waveguide 8 formed of ferromagnetic material so as to produce a field free region therein. The magnetic field for the ferrite block may be provided extending only in the direction of the electron beam so as not to interfere with the electrons in the beam. |
