| 摘要 |
1,146,444. Velocity-modulated tubes. SIEMENS A.G. 14 April, 1966 [15 April, 1965], No. 16296/66. Heading HID. In a microwave/D.C. converter, the microwave signal produces a uniform increase in the drift velocity of an electron beam, the subsequent retardation of which by a gridded collector system provides the D.C. output. In one embodiment (Fig. 1, not shown), the microwave signal is applied to a Cuccia coupler to produce a fast cyclotron wave on an electron beam moving in an axial magnetic field, the cyclotron wave being subsequently converted to a synchronous wave-with a consequent uniform increase in the drift velocity of the beamby an abrupt reversal in sense of the magnetic field. Instead of a Cuccia coupler, a waveguide providing a circularly polarized electric field may be employed. In another embodiment, Fig. 3, which dispenses with a magnetic field, the coupler is in the form of a pair of parallel electrodes twisted about the beam to impose upon the latter a continuous radial deflection, such that the resultant beam rotates around a conical surface, the collector 5 with its grid 6 being of appropriately concave shape to ensure normal receipt of the beam. The coupler in this embodiment may be in the form of a twisted rectangular waveguide (Fig. 4, not shown), arranged such that during a half-cycle of the microwave signal, the beam traverses a 180 degree section of twist. |
