Investigation of a 0.34-THz Quasi-Optical Gyrotron Traveling Wave Amplifier

This article presents the linear and nonlinear theory of a novel quasi-optical gyrotron traveling wave tube (gyro-TWT) at 0.34 THz. The gyro-TWT uses the HE <tex-math notation="LaTeX">_06</tex-math> mode of a confocal waveguide as its operating mode. Based on the dispersion equation, the linear analysis of confocal gyro-TWT is investigated. Meanwhile, the self-consistent nonlinear theory is developed to analyze the performances of the three-stage confocal waveguide gyro-TWTs. To improve the efficiency, the special fan-shaped electron beam is employed and the nonlinear simulation results indicate that the efficiency can be increased to 23.2%, which is significantly higher than the traditional magnetron injection gun (MIG).