Bentian Liu

Design and Experimental Study of a Ka-band Gyro-TWT With Periodic Dielectric Loaded Circuits

The design and experimental study of a Ka-band gyrotron traveling-wave tube (gyro-TWT) amplifier operating in the circular TE01 mode at the fundamental cyclotron harmonic are presented. A periodic dielectric loaded structure is adopted in the interaction circuit of the gyro-TWT to suppress spurious modes TE11 and TE21. A saturated peak power of 156 kW is obtained with a saturated gain of 44 dB, an efficiency of 23.3% in an operating voltage of 67 kV, an electron beam current of 10 A, and a -3-dB bandwidth of 1.8 GHz (~5.2%). The gyro-TWT is found to be zero-drive stable at these operating points and to be characteristic of the excellent purity of the signal frequency spectrum in the operating frequency range.

Experimental Study of High-Power Gyrotron Traveling-Wave Tube With Periodic Lossy Material Loading

The distributed wall loss is a good approach for the suppression of spurious oscillations in gyrotron traveling-wave tube (gyro-TWT). The periodic lossy dielectric loading in the interaction region of gyro-TWT can effectively suppress the spurious oscillations. We designed and employed a periodic lossy-material-loaded circuit in our experimental study of TE_01 Ka-band gyro-TWT. The output characteristics were greatly improved. A peak output power of 290 kW was measured with 56-dB maximum gain, 34.2% efficiency, and 2.1-GHz 3-dB bandwidth when the accelerating voltage was 66 kV and beam current was 13 A.

Experimental study of 290kW Ka-band gyrotron-traveling wave-tube

In our experimental study a periodic medium loaded structure is used as the high-frequency structure of the Ka-band Gyro-TWT. The experimental measurement is carried out when the accelerating voltage is 66kV and the electron beam current is 13A. A peak output power of 293 kW, a maximum gain of 56 dB, an efficiency of 34.2% and a 3dB bandwidth of 2.1GHz are measured.

P3-7: Study of a Ka-Band second-harmonic gyro-TWT amplifier

The design of a Ka-Band gyro-TWT amplifier operating in the circular TE02 mode at the second cyclotron harmonic is presented. The interaction circuit in the design consisted of an axially periodic dielectric and metal loading structure. Large signal simulation shows that the amplifier can generate a saturated peak power of 252kW with a gain of 44dB at 35GHz when utilized a 90kV, 25A, v⊥/v∥=1.2 electron beam from a magnetron injection gun.

Experimental study of a Q-band gyro-TWT

The experimental study of a Q-band gyrotron-travelling-wave tube (gyro-TWT) amplifier operating in the circular TE01 mode at fundamental cyclotron harmonic is presented. A periodic dielectric loaded structure is adopted in the interaction circuit of the gyro-TWT to suppress spurious modes TE11 and TE21. A saturated peak power of 175 kW is obtained corresponding to saturated gain of 53 dB and an efficiency of 38% with -3dB bandwidth of 3 GHz(~7%). The gyro-TWT is found to be zero-drive stable at these operating points.

Design of a Q-band gyro-TWT

The design of a Q-band gyrotron-travelling-wave tube (gyro-TWT) operating in the circular TE01 mode at fundamental cyclotron harmonic are presented. A dielectric-loaded structure is adopted in the interaction circuit of the gyro-TWT to suppress spurious modes TE11 and TE21. A saturated peak power of 220 kW is simulated with saturated gain of 46 dB, efficiency of 30% in operating voltage 70kV, electron beam current 10A and -3dB bandwidth of 3 GHz (~7%).

Effects of loss materials on the output characteristic of Gyro-TWT

The loss characteristics of several loss materials to the backward-wave oscillations modes TE11, TE21 and the operating mode TE01 in Gyrotron traveling wave tube amplifier (Gyro-TWT) are presented in this paper. Effects of these loss materials on the output characteristics of Gyro-TWT are analyzed according to the experimental measurements.

Research of 140 GHz, TE 22.6 mode gyrotron for EAST

The parameters of a 140-GHz TE22.6-mode gyrotron are presented in the article. A single-anode magnetron injection gun (MIG) and the cylindrical resonant cavity operating in the TE22.6-mode are designed for the 140-GHz gyrotron with output power at axial direction. The theoretical efficiency of the gyrotron with operating Voltage 80kV, electron current 40A is about 42%. The gyrotron has been fabricated and will be tested in the future.

Analysis of a W-band low voltage third-harmonic gyrotron oscillator

The paper describes simulation and design of a W-band gyrotron oscillator operating in the circular TE03 mode at the third cyclotron harmonic. A self-consistent nonlinear code and a particle-in-cell (PIC) software were used to investigate the beam-wave interaction. Results of PIC simulations show that the gyrotron oscillator can generate peak power of 12kW at 93.57GHz when utilized a 35kV, 4A, ν ⊥ /ν|| =1.6 electron beam from a magnetron injection gun, and the results of simulations show the gyrotron operates stably in the operating mode.

Design of a W-band third-harmonic gyrotron oscillator

The paper describes simulation and design of a W-band gyrotron oscillator operated in TE₀₃ mode at the third cyclotron harmonic. A self-consistent nonlinear code and a particle-in-cell (PIC) software were used to investigate the beam-wave interaction. Results of simulations show that the gyrotron can generate peak power of 110kW at 93.6GHz when utilized a 40kV, 12A, ν_⊥/ν_∥=1.5 electron beam from a magnetron injection gun, and the gyrotron operates stably in the operating mode.