Gyroresonance amplifiers

Along with gyrotrons, IAP has proposed and brought to a high engineering level the amplifying variety of gyrodevices: gyroklystrons and gyro-TWTs. In their operation concept, gyroklystrons are analogous to conventional klystrons with straight beams. In the gyroklystron, energies of electrons of the helical wave beam are modulated in the input cavity under the action of an external signal, grouped in azimuthal bunches in the drift space, which is free of the microwave field, and then these bunches excite the output cavity. High-power gyroklystrons developed at IAP by I. I. Antakov, E. V. Sokolov, E. V. Zasypkin, I. G. Gachev ensure a pulsed output power of 0.7 MW at a frequency of 35 GHz and up to 0.4 MW at 95 GHz for a gain up to 30 dB and an electron efficiency of up to 30% within a band of up to 0.5%.
IAP proposed the new concept of the gyro-TWT, which is based on the use of waveguides with helical surface corrugations. In the framework of this concept, it is possible to achieve a much wider amplification band compared with gyroklystrons. A unique gyro-TWT based on this concept is designed to work in a pulse-periodic regime with a high level of average power (up to 15 kW). A pulse output power of up to 160 kW was achieved at a frequency of about 34 GHz with a record-breaking bandwidth of more than 2 GHz and an amplification coefficient of about 20 dB. The gyro-TWT is operated at the second cyclotron harmonic and does not require using additional absorbers at a moderate amplification coefficient, which determines their great prospects for practical applications (S. V. Samsonov, G. G. Denisov, and I. G. Gachev).