Miniature thermionic cathode assembly for high frequency linear beam devices

This paper describes a small cathode structure for a 95 GHz TWT. The prototype utilized barium oxide-coated nickel, .002 inch thick and .008 inch wide. But the technique is applicable to small tungsten impregnated cathodes, also. The cathodes were suspended via tensioned tungsten wires anchored to the back of the focus electrode. The cathode is heated by an electron beam striking its rear surface. This beam is emitted from an oxide-coated tungsten hairpin cathode. Data on cathode performance, dimensional stability, and emission stability and uniformity was presented. This technology is adaptable to higher frequency devices.