Theoretical investigation of a high efficiency and broadband sub-terahertz gyrotron

This study investigates the electron dynamics of gyrotron interaction in a tapered waveguide and proposes an interaction structure for a 0.2-THz TE
₀₂
reflective gyrotron backward-wave oscillator (gyro-BWO). The design shows the advantages of high power, continuous and broadband frequency tuning, mode converter free, and inherently possesses mode-selective ability to suppress the potentially competing TE
₂₂
mode. Calculated results indicate that the reflective TE
₀₂
gyro-BWO is capable of generating a peak power of 3.3 kW corresponding to 26.3% interacting efficiency with a broad 3dB-tuning-bandwidth of 6.9 GHz at beam current I
_b
= 0.5 A and beam voltage V
_b
= 25 kV.