Study of a Ka-Band TE11 Mode Gyrotron Traveling-Wave Amplifier

A Ka-band gyrotron traveling wave (gyro-TWT) amplifier with high power and wide bandwidth operated in the fundamental TE11 circular mode is presented in detail. The stability of the gyro-TWT amplifier using linear and nonlinear theory is analyzed. The distributed loss technique is employed in the interaction circuit which guarantees the amplifier zero-drive stability. The effects of the parameters such as input power, driver frequency, magnetic field on the performance of the gyro-TWT is discussed. The simulation results show that the gain and the bandwidth of the designed Ka-band gyro-TWT are about 60.0 dB and 1.4 GHz at constant drive with an axial velocity spread \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$ {{\Delta {v_z}} \mathord{\left/{\vphantom {{\Delta {v_z}} {{v_z}}}} \right.} {{v_z}}} = 5\% $$\end{document}. The peak output power and the corresponding electronic efficiency are about 111 kW and 26.4% respectively for a 70 kV, 6A electron beam at 35 GHz. In addition, the design of the input coupler, a triode-type magnetron injection gun (MIG) and a triple output window are given.