35 GHz third-harmonic gyrotron with a permanent magnet system

A systematic theoretical and experimental study on 35 GHz 45 kV third-harmonic gyrotron with a permanent magnet system is presented in this paper. A complex cavity with gradual transition, and a diode magnetron injection electron gun (MIG) are employed in the gyrotron. The permanent magnet system provided the axial magnetic field of about 4.5 kG in the cavity region. The Ka band third-harmonic gyrotron with a permanent magnet system has been designed, constructed and tested. A peak output power of 147.3 kW was obtained at a beam voltage of 45 kV with beam current of 32.2 A, corresponding to an efficiency of 10.2%.