Abstract
A gyroklystron amplifier with four cavities that operates on high harmonics is described in which a relativistic, rotating shell of electrons interacts synchronously with a high-order azimuthal, cylindrical cavity TE mode. The gain of a fifth-harmonic gyroklystron amplifier has been increased by doubling the length of the drift tubes. The theoretical enhancement is 18 dB (2**6) beyond the previously measured gain of 29 dB. Coupling between cavities has been greatly reduced by removing 75% of the drift tube wall, thereby allowing higher- gain operation before the onset of oscillation due to feedback. The output power level is increased by almost two orders of magnitude to 0. 5 kW, corresponding to a conversion efficiency of 3%.