碳纳米管冷阴极返波管研究

发布时间：2018-03-10 19:24

本文选题：场致发射阴极　切入点：碳纳米管　出处：《电子科技大学》2015年硕士论文　论文类型：学位论文

【摘要】：碳纳米管(CNT)具有优良的场致发射特性,是冷阴极器件的理想阴极材料。为发展碳纳米管冷阴极微波、毫米波电真空辐射源器件,本文对碳纳米管冷阴极的场发射特性进行了研究,设计了一只可工作于8mm波段的碳纳米管冷阴极返波振荡器。主要工作内容如下:(1)对直径为4mm的圆形平面阴极进行了实验测试,获得其最大发射电流密度为127mA/cm2。在实验的基础上,结合粒子模拟软件CST建立了大面积碳纳米管冷阴极的场发射模型。研究了栅网结构对碳纳米管冷阴极场发射性能的影响,获得了矩形栅网结构的优化尺寸,当d=0.1mm,D=4d时,阴极的发射性能较好,电子注通过率约为60%。(2)设计了栅控结构的碳纳米管冷阴极带状注电子枪。分析了栅网结构、阳极电压、聚焦磁场等参数对带状注电子枪性能的影响。优化结果表明该电子枪在阴栅间距0.25mm,栅网电压2.5kV时,能产生工作电压在18kV,电流为1.5A,注半径为0.35mm,电流密度高达17.2A/cm2的带状电子注。(3)结合本征求解法对金属矩形双栅慢波结构的色散特性进行了推导和研究,利用三维粒子模拟软件CST设计了可工作于8mm波段的金属矩形双栅慢波结构。(4)将碳纳米管冷阴极用作返波管的粒子发射源,通过软件Magic和CST仿真设计了可工作于8mm波段的碳纳米管冷阴极返波管。仿真结果表明,该碳纳米管冷阴极返波管能产生工作频率为33.95GHz,输出功率为2.35kW,效率达8.73%的返波信号。
[Abstract]:Carbon nanotube (CNT) has excellent field emission characteristics and is an ideal cathode material for cold cathode devices. In this paper, the field emission characteristics of carbon nanotube (CNT) cold cathode are studied, and an 8 mm band CNT cold cathode backwave oscillator is designed. The main work is as follows: 1) the circular planar cathode with a diameter of 4 mm is experimentally tested. The maximum emission current density is 127 Ma / cm 2. On the basis of experiments, a field emission model of large area carbon nanotube cold cathode is established based on particle simulation software CST. The effect of grid structure on field emission performance of carbon nanotube cold cathode is studied. The optimum size of rectangular grid structure is obtained. When the grid structure is 0.1 mm / d, the emission performance of the cathode is better, and the electron beam passing rate is about 60.0.The grid-controlled carbon nanotube cold cathode ribbon electron gun is designed, and the grid structure and anode voltage are analyzed. The influence of focusing magnetic field and other parameters on the performance of the belt electron gun is obtained. The optimized results show that the electron gun has a gap of 0.25 mm and a grid voltage of 2.5 kV. The dispersion characteristics of metal rectangular double-gate slow-wave structures are deduced and studied by using this solicitation method, which can generate a working voltage of 18 kV, a current of 1.5 A, a beam radius of 0.35 mm, and a current density of up to 17.2 A / cm ~ 2. Using 3D particle simulation software CST to design a metal rectangular double-gate slow-wave structure. 4) the carbon nanotube cold cathode is used as the particle emission source of the backwave tube. Through the software Magic and CST simulation, the CNT cold cathode backwave tube which can work in 8mm band is designed. The simulation results show that the CNT cold cathode backwave-return tube can produce a signal with working frequency of 33.95 GHz, output power of 2.35 kW and efficiency of 8.73%.
【学位授予单位】：电子科技大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TN125

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