Ultra small electron beam amplifiers

While the tube industry has achieved an extraordinary record of success in increasing the power available at a given frequency by about 10 dB per decade, little attention has been devoted to devices with power outputs on the order of one Watt for which there is likely to be an increasing demand for NASA, commercial and military applications as small, portable transmitters and as elements of phased arrays. Typically, when electron beam devices in this power range are built at all, they are virtually the same size and weight as, say, 10 Watt devices; moreover, they are far less efficient since they require nearly the same cathode heater power. A summary will be presented of work performed in-house and by NASA contractors in the emerging technologies of field emission and microfabrication that could provide the basis for the development of a new class of very small, efficient, low power electron beam amplifiers and oscillators.