In this paper, the design and simulation of a high frequency structure for a W-band quasi-optical gyrotron oscillator, which operates at the TE62 mode, has been presented. According to the self-consistent nonlinear theory, the parameters of the high frequency resonator has been designed and optimized. The effects of electron beam voltage, current, velocity spread, magnetic field and electron beam guiding center on the output power and efficiency have been analyzed. The maximum output power and efficiency of the designed gyrotron oscillator is about 39.7kW and 44.1%, respectively.

In this paper, the simulation and design of a diode type magnetron injection gun (MIG) for a W-band CW gyrotron oscillator is presented. The simulation of the MIG, operating at the voltage of 55kV and the current of 4A, is finished with the help of a trajectory program EGUN. The simulation results indicate that the velocity ratio with velocity spread of less than 2.5% is 1.43.

In this paper, a continuous wave (CW) low-voltage fundamental harmonic W-band gyrotron has been designed and simulated with the help of a particle-in-cell (PIC) software CHIPIC. The output power of 33.4 kW with an electron efficiency 37.1% in the PIC simulation is obtained by the designed conventional gyrotron employing a 30-kV, 3-A electron beam which is produced by a triode magnetron injection gun. In addition, a high-power capacity collector being one of the key components of CW gyrotrons has been evaluated and tested. The peak power density on the collector wall using the spreading electron system is about 390 W/cm2 in the hot test. The CW output power of 15.8 kW is achieved with the condition of a 29-kV, 1.8-A electron beam in the hot-test experiment of the designed prototype.

In this paper, the design of a magnetron injection gun (MIG) with a single-anode built for W-band gyrotron oscillator is presented. The simulation of the MIG is finished with the help of a trajectory program EGUN. The simulation results indicate that the velocity ratio with velocity spread of less than 4% is 1.41.

The design of a W-band four-cavity gyroklystron amplifier is presented. The device operates in the fundamental harmonic TE01 circular electric mode. The 70 kV, 6 A beam is produced by a double anode magnetron injection gun (MIG) with an average perpendicular-to-parallel velocity ratio of 1. 5 and a parallel velocity spread of less than 4%. (PIC) simulations have been performed to predict general RF performance for various parameters. The simulated results show that the designed gyroklystron amplifier can produce about 35 dB gain, 800 MHz bandwidth and 100 kW peak output power with power conversion efficiency of 23. 8% for a beam with 4% axial velocity spread.

The design and experiment of a ka-band second harmonic gyroklytron amplifier are reported. The three-cavity 35-GHz second harmonic gyroklystron operates in the TE 021 circular electric mode. Based on the numerical simulation, a three-cavity, second harmonic gyroklystron amplifier prototype has been fabricated. Experiments show a peak output power of 212 kW at 35 GHz with a 3-dB bandwidth of 155 MHz (0.44%) when utilizing a 58 kV, 23 A, v ⊥ / v P = 1.45 electron beam from a magnetron injection gun. The efficiency is approximately 16%, and the gain is about 24 dB.

In this paper, the design and experiment of the conventional electron beam spreading system for W-band gyrotron oscillator collector is presented. The conventional spread system consists of a magnetic shade and two pairs of coils. The particle-in-cell (PIC) simulation of the collector under the conventional spreading system has been finished. The power density distribution of the electron beam on the collector wall has been measured in the hot test of the gyrotron oscillator.

In this paper, the analysis of a conventional W-band gyrotron oscillator operating with TE02 mode has been investigated through the particle-in-cell (PIC) simulation. The influence of the variations of the operating parameters (such as beam voltage, beam current, velocity ratio) on the output power and electron efficiency has been studied in detail. The PIC simulation predicts 33.4kW output power at 94GHz with the electron efficiency about 37%.

Mode competition induces non-stationary oscillations during the operation of a gyrotron backward-wave oscillator (gyro-BWO), which severely reduces its tunable bandwidth and output power. Self-consistent nonlinear theory is used to study the modes-competition mechanism of a W-band fundamental TE01 mode gyro-BWO. Tapered non-resonant interaction circuit structure and loading lossy ceramic are employed to suppress the competing modes, as a way of preventing non-stationary oscillation in the circuit. Systematically optimized interaction circuit is capable of suppressing all the competing modes and can stably operate in the fundamental axial mode of the TE01 mode. Calculation indicates that a peak power of 105 kW and a -3 dB tunable bandwidth of 5.4% are attainable. This is meaningful and provides a theoretical foundation for developing broadband millimeter gyro-BWOs in the applications of counter-measure system, non-destructive detection, plasma diagnosis, material processing, and so on.

In this paper, the design of the conventional electron beam spreading system of the gyrotron collector consisted of the magnetic shade and two pairs of coils is presented. The simulation and experiment of the electron beam distribution on the collector wall of the gyrotron applied to the electron spreading system is completed.

The design of a ka-band gyrotron traveling wave (gyro-TWT) amplifier is presented. The gyro-TWT amplifier with a severed structure operates in the fundamental harmonic TE01 circular electric mode. The beam-wave interaction is studied by using a particle-in-cell (PIC) code. The simulations predict that the amplifier can produce an output peak power of over 155 kW, 22% efficiency, 23 dB gain, and a 3 dB bandwidth of 2 GHz for a 70 kV, 10 A electron beam with an axial velocity spread Δvz/vz=5%.

A quasi-optical mode converter for a W-band TE02 mode gyrotron is designed, fabricated, and tested. The system consists of a step-cut waveguide launcher (cut-in-half circular waveguide) and a doubly curved reflector (an elliptical reflector and a parabolic reflector). Based on the geometric optics principle and the vector diffraction theory, the mode converter is optimized and simulated by using numerical calculations. The simulation results show that the good Gaussian mode is converted from the circular waveguide TE02 mode, and the conversion efficiency is 77.9%. Experimental measurements are performed on a quasi-continuous wave gyrotron operating in the TE02 mode at W-band and show a good agreement with theoretical predictions.

Simulation results of a ka-band high power gyrotron traveling wave amplifier (gyro-TWTA) using the particle-In-cell (PIC) code are reported. The gyro-TWT amplifier with a distributed wall loss structure operates in the fundamental harmonic TE01 circular electric mode. The simulation predicts 135kw output power at ka-band with 19% efficiency, 45 dB gain.

根据回旋管的电子回旋脉塞理论,借助于编写的回旋振荡管自洽非线性注-波互作用计算程序,设计出了工作频率94 GHz、工作电压30 kV、工作电流3A的基次谐波连续波单腔回旋振荡管,工作模式为TE02模.设计的回旋振荡管在电压30.0 kV、电流3.0A、速度横纵比1.5的条件下,获得了31.8 kW的输出功率,电子效率约35％.利用粒子模拟仿真软件对设计的回旋管收集极辅助线包散焦系统进行了粒子模拟仿真分析,模拟结果表明:借助于辅助线包散焦系统可以有效缩短回旋振荡管的轴向尺寸,并使回旋管收集极上的电子束功率密度低于500W/cm2;W波段回旋振荡管收集极的热测试验结果表明:利用粒子模拟仿真获得的收集极上的电子束功率密度分布与其试验测量结果比较吻合.

采用角锥喇叭天线,使用不同输出平均功率的毫米波激光辐照秀丽线虫,采用实时显微摄像系统记录线虫行为学变化,并使用体视显微镜观察线虫细胞形态学变化.受照射后自由活动的秀丽线虫能够快速逃离高功率毫米波的辐照区域.当受输出平均功率为10 W和12 W辐照后,线虫先后出现运动速度增加、运动速度减慢直至身体僵直不动的变化过程.当输出平均功率为5 W时,线虫出现热耐受现象.细胞形态学观察结果显示:辐照后的线虫腹中卵细胞核结构出现不同程度的异常.高功率毫米波辐照可显著影响线虫的行为学特征及细胞形态学,同时说明秀丽线虫是可适用于高功率毫米波生物效应研究的模式生物之一.

The recent experimental results of a Ka-band second harmonic gyroklystron amplifier are presented. The peak output power of 212kW at 35GHz has been measured with a 3dB bandwidth of 155MHz. The tube is operated at electron beam voltage and current of 58 kV and 23 A, respectively. The efficiency is approximately 16% and the gain is about 24 dB.

Objective To explore the effects of acute and continuous high-power millimeter wave radiation on behaviors and lethality in mice.Methods A 34.1GHz millimeter wave source with maximum output mean power of 20W connected with four different calibers of pyramidal horn antennas was used to irradiate mice vertically.A real-time video recording system was used to track the behavioral changes of mice exposed to irradiation.An infrared irradiation thermometer was used to record the abdominal surface temperature of mice,followed by dose-effect analysis.Results All mice showed similar behavior changes when exposed to millimeter wave irradiation with different parameters,but the time required for the first-phase of acute response was different.The surface temperature of mice also increased significantly.With the elongation of the irradiation time,mice died eventually,while the temperature increment reached a peak value(18.43℃).Conclusion Thermal effect of millimeter wave is the major factor causing injury and death of mice,and the time required for the acute intense response and the time of death are depended on the power of millimeter wave and the distance away from millimeter wave.