| 摘要 |
941,691. Velocity-modulated beam tubes. C.S.F.-COMPAGNIE GENERALE DES TELEGRAPHIE SANS FIL. June 18, 1962 [June 21, 1961], No. 23302/62. Heading H1D. A reflex klystron includes a cathode having two portions of its emissive surface axially spaced by such a distance that the transit time of the electrons along said distance is substantially equal to half the period of the operating oscillation. In one form, Fig. 7, a central portion 10 of a circular cathode 11 is depressed a distance d. Alternatively, Fig. 9, the emissive surface is formed by three portions 12, 13, 14, the axial separation of portions 12, 14 being a distance d. In other embodiments, a semi-circular plate of thickness d is placed upon a circular support, sectors of a circle are symmetrically placed on a circular support so as to give alternate raised and lowered portions of the emissive surface, or the cathode is an inclined disc 14, Fig. 11. The axial distance d is arranged to be substantially equal, in millimeters, to 50(V 0 ) ¢/f, where V o is the anode voltage of the klystron in volts, and f is its operating frequency in Mc/s. It is stated that such a cathode minimizes the phenomenon of power hysteresis, that is, the power developed is not single-valued for a given reflector voltage. |
