Demonstration of high average power W-band gyro-amplifiers

The experimental demonstration of a five-cavity, high average power W-band (75-110 GHz) gyroklystron amplifier is reported. The gyroklystron produced 10.2 kW average output power and 31% electronic efficiency in the TE/sub 011/ mode using a 55 kV, 6 A electron beam at 10% RF duty factor. At this operating point, the instantaneous full-width-half-maximum (FWHM) bandwidth was 700 MHz and the saturated gain was 33 dB. At a higher magnetic field, a FWHM bandwidth of 1050 MHz was achieved at 4 kW average power and 10% RF duty factor. These results represent substantial improvement over the performance of the demonstrated four-cavity, 10 kW average power gyroklystron amplifier.