Design and Experiment of a High Power and Broadband Ku-Band TE11 Mode Gyro-TWT

The design and experiment of a high power and broadband Ku-band gyrotron traveling-wave tube (gyro-TWT) amplifier operating in the TE11 mode are presented in this paper. A new-type broadband rotating TE11 mode input coupler is applied to excite operating mode and a broadband three-disk beryllium oxide ceramic output window is used in the designed gyro-TWT. In order to suppress the potential oscillations, expand working bandwidth, and improve the heat dissipation capability of high frequency system, a periodic beryllium oxide and silicon carbide composite lossy ceramic rings loaded high-frequency circuit with a nonlinear small change output taper is adopted in the gyro-TWT. When the beam voltage is 70 kV and the beam current is 12 A, the experiment of this Ku-band gyro-TWT developed shows that the measured maximum output average power is similar to 20 kW at the frequency 16 GHz, corresponding to a maximum output pulse power of similar to 200 kW (10% duty ratio), a gain of 43.0 dB and a maximum efficiency of 23.8%, -3-dB saturation gain bandwidth of 2.6 GHz (similar to 16.3%), and -1-dB saturation gain bandwidth of 1.5 GHz (similar to 9.4%). Under the condition of 10-W constant input power driven, the measured -3-dB constant driven bandwidth is 1.4 GHz (similar to 8.8%).