Terahertz harmonic gyrotron based on spoof surface plasmon

Gyrotron is based on the principle of relativistic electron cyclotron maser. With the working frequency increasing to terahertz band, the mode competition problem is caused by the interaction between harmonic cyclotron electrons and high order electromagnetic modes. In order to solve this problem, the interaction cavity of harmonic gyrotron based on spoof surface plasmon (SSP) is proposed in this paper, and its eigenmode frequency is studied, the concept of Band Gap is proposed. If the competition frequency is in the stopband, the competition mode will not be generated. Finally, the Particle-in-cell (PIC) simulation is carried out, which proves that the structure can make the terahertz gyrotron work in the single mode in state of high harmonics.