光子晶体回旋管相关问题的研究

发布时间：2018-06-22 13:02

本文选题：回旋管 + 光子带隙谐振腔　；参考：《电子科技大学》2016年博士论文

【摘要】：太赫兹作为介于毫米波与红外光之间的过渡波段,它既具有毫米波的特性同时又有光的特性,具有重要的应用前景,它的产生和应用是目前国际上的研究热点。电子回旋器件已被证明是目前最有可能产生大功率太赫兹信号的器件。为了增大注-波互作用腔体的尺寸,增大功率容量,减小尺寸共渡效应引起的一系列问题,太赫兹回旋管通常工作于高阶模式。然而高阶模式工作时的相应竞争模式较多,为解决高阶模式的模式竞争严重问题,新型回旋管高频结构的研究成为必要。光子晶体结构由于具有光子禁带特性,通过在其禁带中引入缺陷的方式,可以很好的实现模式选择特性,降低模式密度,减少模式竞争,从而解决太赫兹回旋器件过模工作引起的一系列问题。因此,光子晶体回旋管相关问题的研究具有非常重要的意义。本文根据固体物理的晶格理论,对光子晶体结构的带隙特性进行了研究,通过引入缺陷的方式,利用光子晶体带隙特性设计了0.1THz工作于类TE04模式的光子带隙谐振腔,并对该光子晶体回旋管的电子光学系统及输出窗等结构进行了研究分析。本文的主要研究内容及创新之处概述如下:1、从麦克斯韦方程组出发,推导了光子晶体结构的本征方程,并研究了光子晶体结构的缩放法则等特性。根据固体物理中的晶格理论求解出二维光子晶体结构介质材料及金属材料结构的带隙特性,通过理论及仿真相结合的方法获得无氧铜金属柱三角形晶格及正方形晶格TE波全局带隙图。2、为了获得更好的模式选择性,对二维正三角形阵列光子晶体结构进行了研究。根据二维三角形晶格TE波全局带隙图,通过等效半径的方法,得出不同缺陷情况时光子晶体全局禁带内所存在的模式分布图。选择竞争模式较少且模式分隔度较大的角向对称性良好的TE04模为工作模式。通过理论分析及软件仿真研究了光子晶体谐振腔中的模式分布,并与圆柱腔进行对比,得出所设计的光子晶体谐振腔中TE04模场分布与圆柱波导中TE04模场分布很接近。通过回旋管相关理论定出工作于0.1THz波段时,该回旋器件的工作电压,电流,磁场,引导中心半径等工作参数。3、根据0.1THz光子晶体回旋管高频结构对电子注性能要求,理论分析了该光子晶体回旋管的磁控注入式电子枪结构,根据其理论分析结果,初步确定出工作于0.1THz回旋管的电子枪结构。通过软件仿真对其初始结构进行优化分析,设计出满足该回旋器件需求的电子枪结构。并介绍了已应用于实验中的两个电子枪结构,即应用于W波段回旋管引导中心半径3mm,横纵速度比为1.4,速度离散小于3%的单阳极电子枪结构和应用于420GHz二次谐波回旋管中引导中心半径1.95mm,横纵速度比为1.4的双阳极电子枪。实验测得结果均较为理想,与理论设计相符,证明所编程序仿真优化电子枪的正确性。4、介绍了几种常用的输出窗结构,采用模式匹配的方法求得计算单窗片输出窗传输理论,通过理论与现有商业软件仿真结果进行对比验证该理论方法的正确性,此理论方法相较于商业软件仿真方法更加迅速快捷,从而大大降低了工程设计周期和计算成本。根据单窗片输出窗理论,采用传输矩阵级联的方法得出多窗片传输理论。通过合理的设计多窗片结构,获得TE04模式反射小于-20dB的带宽为9.45GHz,相对带宽为10%的双窗片结构;通过对三窗片结构进行优化设计,得出在78-131.4GHz范围内对TE04模反射均小于-20dB的三窗片结构,该窗片-20dB带宽为53.37GHz。对于输出模式为高斯模式的器件,输出窗通常采用布鲁斯特窗,而对于存在于波纹波导中的高斯模式通常为HE11模,为了更好的传输HE11模式,通过将布鲁斯特窗与波纹波导相结合的方式,设计出一款新型布鲁斯特窗。采用矢网分析仪对该新型布鲁斯特窗冷测得出,在频段84-102GHz范围内的反射均小于-22dB,通过理论仿真及实验结果可知,该新型布鲁斯特窗具有很高的带宽,适用于对带宽要求更高的行波管返波管等器件。
[Abstract]:Terahertz, as a transition band between millimeter wave and infrared light, has the characteristics of both millimeter wave and light, which has an important application prospect. The generation and application of THz is a hot topic in the world. Electronic gyrotron has been proved to be the most likely device to produce high power terahertz signal at present. Increasing the size of the cavity with the injection wave interaction, increasing the power capacity and reducing a series of problems caused by the size common effect, the terahertz gyrotron usually works in the high order mode. However, there are more competition modes in the high order mode. In order to solve the severe competition problem of the high order mode, the high frequency structure of the new gyrotron is studied. As a result of the photonic band gap, the photonic crystal structure can realize the mode selection characteristic, reduce the mode density and reduce the mode competition by introducing the defect in the band gap. Thus, a series of questions caused by the overmold work of the terahertz gyrotron are solved. Therefore, the research on the related problems of the photonic crystal Gyrotron It is of great significance. Based on the lattice theory of solid physics, this paper studies the band gap characteristics of the photonic crystal structure. By introducing the defect mode, the photonic band gap resonant cavity of 0.1THz in the TE04 mode is designed by the band gap characteristics of the photonic crystal, and the electronic optical system and output of the photonic crystal gyrotron are also given. The main contents and innovations of this paper are summarized as follows: 1, from the Maxwell equation, the intrinsic equation of the photonic crystal structure is derived, and the scaling law of the photonic crystal structure is studied. The two-dimensional photonic crystal structure medium is solved according to the lattice theory in solid physics. The band gap characteristics of material and metal structure are obtained by combining theoretical and simulation methods to obtain the triangular lattice of oxygen free copper metal column and the global band gap diagram of square lattice TE wave.2. In order to obtain better mode selectivity, the two-dimensional triangular array photonic crystal structure is studied. According to the global band of the two-dimensional triangular lattice TE wave Through the method of the equivalent radius, the pattern distribution of the photonic crystal in the global band gap is obtained by the method of equivalent radius. The mode of TE04 mode with good angular symmetry is selected as the working mode with less competition mode and larger mode separation degree, and the mode distribution in the photonic crystal resonator is studied through theoretical analysis and software simulation. Compared with the cylindrical cavity, it is concluded that the TE04 mode field distribution in the designed photonic crystal resonator is close to the TE04 mode field distribution in the cylindrical waveguide. The working voltage, current, magnetic field, guiding center radius and other working parameters of the gyrotron are determined by the theory of gyrotron related to the 0.1THz band, which is based on the 0.1THz photonic crystal gyrating. According to the theoretical analysis results, the structure of the electron gun which works on the 0.1THz gyrotron is preliminarily determined according to the theoretical analysis results, and the initial structure is optimized by software simulation, and the electronics to meet the needs of the gyrotron are designed. The structure of the two electron gun, which has been applied to the experiment, is introduced, which is used in the W band gyrotron guide center radius 3mm, the transverse and longitudinal velocity ratio of 1.4, the velocity discrete less than 3% of the single anode electron gun structure and the dual anode electron gun used in the 420GHz two harmonic gyrotron with the guide center radius 1.95mm and the transverse longitudinal velocity ratio of 1.4. The experimental results are all ideal and agree with the theoretical design. It proves that the program compiled and optimized for the correctness of the electronic gun is.4. Several common output window structures are introduced. The transmission theory of single window output window is calculated by mode matching method. The theoretical method is compared with the existing commercial software simulation results to verify the theoretical method. The theory method is more rapid and faster than the commercial software simulation method, thus greatly reducing the engineering design cycle and calculation cost. According to the single window output window theory, the multi window transmission theory is obtained by the transfer matrix cascade method. The TE04 mode reflection is less than -20dB through the rational design of the multi window structure. With a bandwidth of 9.45GHz and a double window with a relative bandwidth of 10%, by optimizing the three window structure, the three windows of the TE04 module in the 78-131.4GHz range are less than -20dB, and the -20dB bandwidth of the window is 53.37GHz. for the output mode of Gauss mode, and the output window is usually used as a window, and for the output window. The Gauss mode in the corrugated waveguide is usually HE11 mode. In order to transmit the HE11 mode better, a new Brewster window is designed by combining the Brewster window with the corrugated waveguide. A vector net analyzer is used to test the new Brewster window, and the reflection in the range of 84-102GHz is less than -22dB. Theoretical simulation and experimental results show that the new Brewster window has a high bandwidth and is suitable for traveling wave tube backward wave tubes with higher bandwidth requirements.
【学位授予单位】：电子科技大学
【学位级别】：博士
【学位授予年份】：2016
【分类号】：TN12

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