Design and Performance of a Three-Cavity Gyroklystron Amplifier

Millimeter-wave power reduction using fast-wave amplifiers has shown a large amount of experimental progress in the last decade. Recent studies have focused on the gyroklystron amplifier (GKA) and the gyro-traveling wave tube (gyro-TRT). These devices eliminate the conventional slow-wave circuit by using the periodic motion of the electrons, induced by external fields applied in the interaction region, to couple (synchronize) a natural beam resonance to a selected waveguide mode. With the gyro-devices, a axial magnetic field is used to couple the fast cyclotron wave on the beam to an appropriate transverse electric (TE) waveguide mode. The fast-wave amplifiers are able to generate increased millimeter wave power levels, since their coupling mechanism does not require the small transverse dimensions of the slow-wave circuit; indeed, simple structures such as large scale cavities or lengths of waveguide can be used for gyro-devices. The Naval Research Laboratory is presently pursuing a program to investigate the performance of gyroklystron devices. The main emphasis is on amplifiers; however, locked oscillator performance is also being studied. Supersedes AD-A168 629.