【作者】 殷海荣；

【导师】 宫玉彬；

【作者基本信息】 电子科技大学 ， 物理电子学， 2007， 博士

【摘要】 由于无法使用完全自动化的工艺实现加工，行波管的成本一直居高不下，并且一致性和可靠性差，加之随着频率的提高，尺寸共渡现象给电子注的渡越带来了障碍，使得中高功率行波管在毫米波段的加工成本成倍增加，并难以在亚毫米波及以上频段实现工作，因而成本和尺寸共渡因素严重限制了行波管的应用和发展。使用能够利用自动化工艺加工的新材料和新结构是降低行波管成本最理想的办法，而解决尺寸共渡现象，突破现有频率上限，则需要建立在新的电磁传输机理之上。光子晶体是一种具有特殊电磁响应的新材料和新结构，它的出现为实现行波管的自动化加工和一致性生产，以及突破现有频率上限带来了新的希望。光子晶体为发展现有行波管提供了三种可能性：首先，光子晶体结构改变了电磁波在介质中的场分布，因此可以改变行波管的介质负载度，利用光子晶体代替介质材料，可以改善介质基底印制电路行波管中业已存在的效率问题，实现行波管的印刷电路化，因而可以降低行波管的成本，并提高产品的可靠性和一致性；其次，当工作频率特别高时，电磁波在金属波导中传播的衰减加剧，这时可以使用介质光子晶体来取代金属波导，提高慢波电路的传输性能；第三，为了解决尺寸共渡问题，可以利用高次模式工作以便获得更大的电子束通道，保证电子注的流通率，但当使用金属波导慢波电路的高次模式工作时，则会存在着模式竞争问题，如果利用光子晶体代替金属波导，存在于光子晶体禁带中的高次模式则可以实现单模工作，这为解决尺寸共渡问题提供了可能。本论文以光子晶体在行波管中的应用为研究对象，研究内容包括有限光子晶体中的电磁波模式和传播行为、光子晶体行波管慢波电路的基本原理和设计原理、带状束和圆电子束光子晶体行波放大器的具体设计，以及大截面慢波电路行波管电子光学系统的设计。本文的组织结构为：第一章为绪论，介绍现有行波管的困难和光子晶体的概念和特性，阐明论文的研究意义和范围。第二章针对有限光子晶体进行研究，具体内容包括光子晶体金属波导、开敞结构有限光子晶体和具有缺陷的有限光子晶体中的电磁波模式和电磁波传播。第三章讨论了光子晶体行波放大器的基本原理，确定了光子慢波电路的三层基本结构，讨论了光子晶体慢波电路的设计困难和解决办法，和光子晶体慢波电路的本征值设计方法和散射参数设计方法。第四章讨论了利用缺陷模式工作的二维光子晶体栅慢波电路和光子晶体对插销带状束行波放大器，和光子晶体-截止波导曲折线慢波电路行波放大器的设计方法。第五章首先讨论了圆电子束环类慢波电路的拓朴结构，包括介质加载环板慢波电路和四类发展型沟道梯型慢波电路，在这些讨论的基础上，选择了准环杆结构作为圆电子束光子晶体慢波电路的基本慢波结构，并对使用高阻抗表面光子晶体的准环杆慢波电路进行了设计和讨论。由于使用光子晶体作为慢波电路会给行波管带来大截面问题，因此第六章对具有大截面慢波电路的行波管的电子光学系统设计进行了讨论。该章以一个大截面慢波电路行波管设计实例为基础，从定义和计算相关性系数和敏感性系数入手讨论了如何利用轨迹计算软件快速而有效地进行设计和在慢波电路结构与电子光学系统结构之间进行折衷和平衡。第七章是结论。更多还原

【Abstract】 Because can not be machined automatically, the cost of traveling wave tubes (TWTs) is very high, and the products are not completely consistent, so does the reliability. Further more, the transit of electrons becomes more difficult in TWTs when operating frequency is high. As a result, the cost of TWTs with middle or high outputting power is doubled inside millimeter-wave band, and the design of TWTs inside short millimeter-wave seldom succeeds. High cost and problem of electron transit extensively limit the application range and the development of TWTs. The cost of TWTs will decrease sharply if a kind of new material or structure which can be machined automatically is used. But the solution of electron transit inside high frequency band only bases on new mechanism of electromagnetic wave propagation.Photonic crystals (PhC) are new artificial materials with special electromagnetic response characteristics. Intruducing PhC into TWTs brings new possibility of decreasing cost and resolving problem of electron transit. First, the field distribution of PhC is diffirent from dielectric; the efficiency will increase if the dielectric of printed dielectric-base TWTs is replaced by PhC. Second, when operating frequency is inside or higher than THz band, the propagation attenuation of electromagnetic wave in metal waveguide will be high, but will be very low in PhC strucutred by dielectric. At last, operating with single higher mode is feasible in TWTs made up of PhC slow-wave circuit; accordingly, the problem of electron transit will be resolved based on the bigger beam tunnel available in PhC slow-wave circuit.The theme of this dissertation is TWTs with PhC circuit. The studied details include the modes and the propagation of electromagnetic waves in finite PhC, the basic theory and the design of PhC TWTs, and the design of electron optics for TWTs in which the cross-section of slow-wave circuit is big. The structure of this dissertation is presented in the following:Chapter 1 is introduction. In chapter 1, the background of research and the obstacles of present TWTs will be firstly explained. Then, the significance and the researching scope of this dissertation will be presented. In chapter 2, the main course is finite PhC. The modes and the propagation of electromagnetic waves in PhC metal waveguide, opening finite PhC and finite PhC with defect will be discussed.In chapter 3, the basic theory of PhC TWTs will be discussed. The basic three-layer structure of PhC TWTs will be put forward. The difficulty of design and the solving way, and the design ways by calculating eigenvalues and by calculating parameters of scattering matrix will be discussed.Three kinds of PhC TWTs with ribbon beam will be presented and discussed in chapter 4. The two kinds of PhC TWTs are the interdigital slow-wave structure and metal grating slow-wave strucutre with two-dimensional dielectric PhC, and the meander line slow-wave structure with PhC and cutoff-waveguide structures.In chapter 5, the topo structures of ring slow-wave structures based on ring-plane structure and Tunneladder slow-wave circuit will be firstly discussed. Then, the PhC slow-wave structure combining ring-bar slow-wave structure and high impedance surface PhC will be studied.For the usage of PhC in TWTs will make the cross-section of slow-wave strucutre become more bigger, in chapter 6, the electron optics system of TWTs with PhC slow-wave structure will be studied. An example will be presented, and the way will be shown by defining and calculating the coeffients of relation and sensitivity through the results of numerical codes.The chapter 7 is conclusion.更多还原