Output coupling circuit for microwave tube apparatus

961,964. Velocity-modulated beam tubes. VARIAN ASSOCIATES. Aug. 8, 1960 [Aug. 6, 1959], No. 19529/63. Divided out of 961,961. Drawings to Specification. Heading H1D. A klystron amplifier for broad-band response having at least four resonant driver cavities arranged for successive interaction with an electron beam, the resonant frequencies of the cavities being distributed over the operating frequency band of the amplifier, the loaded " Q "s of the cavities that are resonant at frequencies within a lower part of the band decreasing with increasing resonant frequency, and the loaded " Q "s of those cavities that are resonant at frequencies within a higher part of the band increasing with increasing resonant frequency. The resonant frequency of the cavities may increase from cavity to cavity in the direction of travel of the beam electrons or the second such cavity may have the lowest loaded Q. The tube may be constructed as described-in Specification 961,961.