Numerical Simulation of MIG for 42 GHz, 200 kW Gyrotron

A triode type magnetron injection gun (MIG) of a 42 GHz, 200 kW gyrotron for an Indian TOKAMAK system is designed by using the commercially available code EGUN. The operating voltages of the modulating anode and the accelerating anode are 29 kV and 65 kV respectively. The operating mode of the gyrotron is TE₀₃ and it is operated in fundamental harmonic. The simulated results of MIG obtained with the EGUN code are validated with another trajectory code TRAK.     

2．4GHz电压控制振荡器的设计与仿真

通过分析测量BJT的S参数与稳定因子定,并利用已测量的BJT输出阻抗ZOUT来设计输出匹配电路,使整体电路在2．4GHz的频率上产生振荡。利用ADS软件对电路进行仿真。达到在BJT特定的偏压下。仍在2．4GHz的频率上持续振荡。并可利用电压的变化来控制其振荡频率的目的。     

Design of a 5.305 GHz Dielectric Resonator Oscillator with Simulation and Optimization

The design of a 5.305 GHz series feedback free running dielectric resonator oscillator （DRO） is presented. Its simulation and optimization are realized by obtaining the unloaded Q factor of the cavity dielectric resonator （DR） and analyzing the linear and nonlinear models of the DRO. CAD packages of DR_Rez and Agilent Advance Design System （ADS） are used and the best tradeoff among the output power, phase noise, and frequency stability is achieved. With the result of simulation, a physical oscillator prototype is constructed. The measured results show the good agreement with those of simulation.     

A 100 kW, 140 GHz pulsed gyrotron

The design and operation of a 100 kW, 140 GHz pulsed gyrotron are reported. To our knowledge, this is the highest frequency at which high gyrotron output power (>-100 kW) has been achieved. Results are presented for gyrotron operation in the range of magnetic field from 4 to 7 T, voltage from 23 to 80 kV and current up to 7.5 A. Near a value of magnetic field of 5.4 T, and output power of 100 kW was obtained at 140.4 GHz in single mode operation in the TE₀₃₁ resonator mode.     

360 GHz返波管的研究

对采用齿状光栅结构的慢波电路进行了研究,该结构在电子束与光栅表面接近的情况下有一定的通过率。在求得最大耦合阻抗条件下,设计了一种工作在360 GHz的返波管,通过对互作用电路的耦合阻抗的分析,可以减小亚毫米波及太赫兹真空电子学辐射源对阴极发射电流密度的要求。当工作电压为19.5 kV,工作电流75 mA时,PIC模拟结果得到了8 W的平均功率输出,考虑阴极为脉冲工作时,该器件在360 GHz可以得到4 mW的平均功率输出。     

A High-Gain, 28GHz, 200kW Gyroklystron Amplifier

A design study of a high efficiency/gain gyroklystron amplifier is performed to demonstrate amplified radiation power of 200kW operating at 28GHz. A key design feature of the present gyroklystron amplifier is that the amplifier is designed to be high gain so that it can be saturated by a low power solid state power amplifier. A non-linear, time-dependent, large signal numerical code is used to predict tube performance. Simulations predict that a stable amplifier radiation power of 214kW is produced with a saturated gain of 54dB, an electronic efficiency of 37%, and a frequency bandwidth of 0.3% from a five-cavity gyroklystron amplifier. The amplifier gain is found to be very sensitive to a beam velocity spread.     

An Iron-Free Magnetron-Injection-Gun for a 28GHz, 200kW Gyroklystron Amplifier

A design study of a double-anode magnetron-injection-gun is performed to incorporate the electron gun into a high power 28GHz gyroklystron amplifier operating at 70kV and 8.2A. The electron gun is designed to be used in a tapered magnetic field in the cathode region produced from an iron-free superconducting magnet. An electron trajectory code predicts a beam axial velocity spread of 5.9% at α = 1.5, 70kV, 8.2A and 10.4kG, which is a high quality electron beam suitable for the high gain, high efficiency, five-cavity gyroklystron amplifier. The successful design of the high quality electron gun is attributed to a longer gap between the modulating anode and the grounded anode compared with the case of the first 28GHz electron gun built with an iron enclosed electromagnet.     

三极管特征频率下1GHz振荡器设计与仿真

三极管振荡器一般工作在截止频率附近，这时虽然能够输出较大信号，获得较好的频率稳定度，但是电路中滤波器性能的好坏直接影响输出的高次谐波干扰，而且这种设计思想大大限制了三极管往更高频率上的应用。谩计了在特征频率工作下的三极管振荡嚣，严格限制了高次谐波干扰。建立了射频三极管分布参数、封装参数模型，利用上述模型模拟了三极管特征频率下工作的振荡器振荡频率，输出电压与电源电压、振荡频率与电源电压、振荡频率与基极电感、输出电压与基极电感的关系。最后得出模拟与实验测试一致的结果。     

Development of 170 GHz/500 kW gyrotron

A development of 170GHz/500kW level gyrotron was carried out as R&D work of ITER. The oscillation mode is TE_31,8. In a short pulse experiment, the maximum power of 750kW was achieved at 85kV/40A. The efficiency was 22%. In the depressed collector operation, 500kW/36%/50ms was obtained. The maximum efficiency of 40% was obtained at P_RF=470kW whereas the power decrease by the electron trapping was observed. Pulse extension was done up to 10s at P_RF=170kW with the depressed collector operation. The power was limited by the temperature increase of the output window.     

110 GHz gyrotron with a built-in high-efficiency converter

A 110 GHz 1 MW pulse gyrotron has been elaborated. A built-in electrodynamic duct consisting of a new type quasi-optical converter and three matching mirrors transforms operating mode TE_15,4 into a gaussian beam going through the output window. The efficiency of the duct (ratio of the gaussian beam power outside the gyrotron to the total microwave power at the output of the cavity) is about 95%. A system consisting of the gyrotron and an outer mirror transmission line is proved to have efficiency (ratio of the microwave power measured by calorimeter at the end of line to the power of the electron beam) more than 40%.     

CONCEPTUAL DESIGN STUDIES OF AN 84 GHz, 500 kW, CW GYROTRON

The feasibility of an 84 GHz, 500 kW, CW gyrotron for ECRH on an experimental tokamak will be presented in this paper. Mode competition and mode selection procedures are carefully investigated by considering various candidate modes and the TE_10,4 mode is chosen as the operating mode. A conventional cylindrical cavity resonator with weak input and output tapers and parabolic roundings is considered for interaction studies. Self-consistent, both single mode and time-dependent, calculations are carried out and power and efficiencies are computed for a typical set of beam parameters. The results show that an output power of well over 500 kW, CW and efficiency around 40% can be reached without a depressed collector.     

Conceptual design of a 42 GHz, 200 kW gyrotron operating in the TE5,2 mode

This paper deals with the conceptual design of a 42 GHz, 200 kW continuous wave gyrotron operating in the TE _5,2 mode with radial output coupling. The basic motivation and selection criteria are discussed and the design of the resonant cavity, magnetron injection gun, radio frequency (RF) guiding system, quasioptical output coupler and RF window is presented.     

Chaotization of Oscillations in a Single-Frequency Millimeter-Band Impact Avalanche and Transit-Time Diode Oscillator under the Influence of a Low-Frequency Harmonic Oscillation

The change in the oscillation spectrum of an oscillator based on an impact avalanche and transit-time (IMPATT) diode of the 7-mm range under the action of a low-frequency harmonic oscillation (3 MHz) in the supply circuit of the diode is studied experimentally. It is demonstrated that, if the low-frequency oscillation amplitude exceeds the trigger negative voltage and the working point in the diode volt–ampere characteristic is located either near the trigger current (trigger negative voltage) or far from it, pulsed oscillation mode is established and, consequently, oscillations are chaotized.     

Design of a 24 GHz, 25-50 kW Technology Gyrotron Operating at the Second Harmonic

The preliminary design of a moderate (25-50 kW) gyrotron operating at the ISM (industrial, scientific, medical) frequency of 24.1 GHz is presented. Operation at the second harmonic is considered so that one can obtain radiation at the given frequency with only half the magnetic field required.     

Electronic Tuning of the Punch-Through Injection Transit-Time (PITT) Microwave Oscillator (Short Papers)

Experimental results of the dynamic resistance and capacitance of p+-n-p+ punch-through injection transit-time (PITT or BARRITT) diodes are presented. A method of predicting the oscillator electronic tuning from the change in the device capacitance is outlined and verified experimentally at X band.     

对调Q激光器泵浦的光学参量振荡器(OPO)的计算机模拟

在倍频调QYAG激光器作为OPO泵浦源的情况下,对锂酸铌OPO的振荡过程进行了计算机模拟。有的结果与实验吻合较好。     

Theoretical Analysis and Computer Simulation of Different Balance Bridge Voltage Controlled Crystal Oscillator

Q－double effect of different balance bridge voltage controlled crystal oscillator(DBVCXO)is quantitatively analysed by the computer simulation.     

2．5kw质子交换膜燃料电池系统建模、仿真及其优化研究

本文介绍了2．5kW质子交换膜燃料电池（PEM Fuel Cell---PEMFC）系统的建模、仿真及其优化等研究工作，包括燃料电池堆的动态仿真模型建模过程、湿度和温度控制电路的设计过程。对湿度控制电路的新型模型参考控制策略的建模、仿真及应用表明，该控制策略能够显著提高系统供电质量，以及保证系统长时期运行的稳定性。     

A 110 GHz ozone radiometer with a cryogenic planar Schottky mixer

A total power radiometer for monitoring the stratospheric ozone spectral line at 110 GHz is presented. Special features such as a cooled planar Schottky mixer as the front end and efficient reduction of standing waves in the quasi-optics are discussed in detail. The noise temperature of the receiver is 530 K (single sideband), and the total bandwidth of the receiver is 1 GHz. A dual acoustooptical spectrometer is used for the signal detection     

2kW连续波磁控管设计与仿真

本文介绍了一种用于工、农业加热的连续波磁控管的研制过程,该磁控管工作频率2450MHz,输出功率2kW。该磁控管采用轴向能量输出结构,作为辐射天线插入激励波导中进行能量输出,阴极采用直热式螺旋形碳化钍钨阴极,整管体积小、重量轻、结构紧凑,便于安装和使用。