Optimization of multistage harmonic gyrodevices

Summary form only given, as follows. In low voltage gyrodevices operating at high cyclotron harmonics the electrons are weakly coupled to the synchronous harmonic of an electromagnetic field. To realize efficient operation of a device it is necessary to compensate for this weak coupling by increasing the resonator Q-factor. When the required Q-factor is on the order of the ohmic Q-factor, the optimization of gyrotron parameters should be modified by taking into account ohmic losses of the microwave power. In the present paper this modification has been done and the optimization of two- and three-cavity gyrodevices operating at cyclotron harmonics has been considered.