The super power CW amplitron

By using a newly developed high dissipation cooling technique combined with the well known high efficiency performance of the Amplitron, an electron tube has been developed at 3000 Mcs capable of generating large amounts of CW microwave power. CW power output exceeding 400 kilowatts has been obtained with an efficiency of 70% and gain of 9 db. Operation over a wide range of power output, from 150 to 400 kilowatts, has been achieved with substantially constant efficiency. Unique design features of the tube include high dissipation vanes which operate at a dissipation density of 5 kilowatts/cm², a cold water cooled cathode which can withstand electron bombardment power density of several kilowatts/cm², and an output window assembly which transmits power by radiation into a compact test load. The tube consists of dual cascaded Amplitron network assemblies in a common vacuum envelope. Gain is trimmed to equalize the power generated and dissipated in each stage. Since all parts of the structure are water cooled and no heater power is required, the resulting device is a cold metallic vacuum enclosure with potentially long life capability. Other typical properties of the Amplitron such as low operating voltage, low phase pushing, and phase linearity are preserved in the high power tube. This work has been supported by the Rome Air Development Center under Contract Number AF 30