220 GHZ microfabricated sheet beam amplifier gratings

Summary form only given. The NRL Microfabricated 220 GHz Vacuum Electronic Amplifiers project is aimed toward demonstrating a 50 watt CW output power slow-wave amplifier at 220 GHz based on a sheet electron beam. Slow-wave amplifiers are very compact owing to their intrinsically small electromagnetic circuit features. These small features, however, pose challenges for high power generation because of the high power densities required. As a material, copper has desirable properties for mmW vacuum electronics: Low mmW resistive loss, high thermal conductivity, ease of fabrication, and vacuum compatibility. A suite of microfabrication techniques is being developed in-house for accurately fabricating mmW structures from OFHC copper for high power density.