超材料衰减结构在折叠波导慢波结构中的应用

论文总字数：29851字

摘 要

人工超材料利用材料几何结构，可以任意设计材料特性，实现特定的电介质常数与磁介质常数。人工超材料已在微波、毫米波技术领域得到深入研究，且构成实用元器件。人工超材料为解决行波管的困难带来了新的希望，有望解决传统VED在向高频段、小型化、大功率等方向发展中所面临的诸多问题。超材料吸波结构在自由空间已经有了众多发展与应用，具有良好的吸波性能。但如何将超材料吸波结构应用在行波管器件中，取代原有衰减器结构，尚未有研究见诸报道。

本文对超材料吸波器在行波管中的应用进行了研究和分析，在原有人工超材料设计的基础上进行改进，以便适配波导结构。该结构为三层结构，顶层为金属开口谐振环，中间层为硅介质层，底层是金属背板。经过理论分析及参数优化，得到特定频段吸波效果较好的参数，并应用于折叠波导慢波结构来吸收截断处的反射波，从而抑制自激振荡，实现折叠波导的一体化制作，增加集成度，提高可靠性。

本文结构介绍如下：第一章介绍了研究背景及现状，第二章对超材料吸波理论及分析方法进行了简单介绍，第三章提出一种超材料吸波结构，经过参数优化和调试应用于折叠波导慢波结构，实现了行波管器件中的吸波功能，第四章分析了加载了衰减器的折叠波导性能，最后一章为总结和展望。

本文利用超材料结构，最终设计出了吸波中心频率34.0GHz，带宽约0.8GHz的超材料吸波结构，应用于折叠波导中，实现了返波吸收，很好的实现了取代传统衰减器的功能，为超材料结构在行波管中的研究，奠定了基础。

关键词：折叠波导行波管，超材料，吸波器

Abstract

Artificial metamaterials utilize material geometry to arbitrarily design material properties to achieve specific dielectric constants and magnetic dielectric constants. Artificial metamaterials have been thoroughly studied in the field of microwave and millimeter wave technology, and constitute practical components. Artificial metamaterials have brought new hopes for solving the difficulties of traveling wave tubes, and it is expected to solve many problems faced by traditional VEDs in the development of high frequency band, miniaturization and high power. The metamaterial absorber has been developed and applied in free space, and has good absorbing properties. However, how to apply the metamaterial absorbing structure to the traveling wave tube device instead of the original attenuator structure has not been reported.

In this paper, the application of the supermaterial absorber in the traveling wave tube is studied and analyzed, and the original artificial metamaterial design is improved to adapt the waveguide structure. The structure is a three-layer structure, the top layer is a metal-opening resonant ring, the middle layer is a silicon dielectric layer, and the bottom layer is a metal ground layer. After theoretical analysis and parameter optimization, the parameters with better absorbing effect in specific frequency bands are obtained, and applied to the folded waveguide slow wave structure to absorb the reflected waves at the cutoff, thereby suppressing the back-wave oscillation, realizing the integrated fabrication of the folded waveguide and increasing the integration. Degree, improve reliability.

The structure of this paper is introduced as follows: The first chapter introduces the research background and the status quo. The second chapter introduces the theory and analysis method of the absorbing material of metamaterials. The third chapter proposes a supermaterial absorbing structure, which is optimized by parameters and debugged. In the folded waveguide slow-wave structure, the absorbing function in the traveling wave tube device is realized. In the fourth chapter, the performance of the folded waveguide loaded with the attenuator is analyzed. The last chapter is the summary and prospect.

In this paper, using the metamaterial structure, a metamaterial absorbing structure with a absorbing center frequency of 34.0 GHz and a bandwidth of about 0.8 GHz is designed. It is applied to the folded waveguide to achieve back-wave absorption, which is a good substitute for the traditional attenuator. The function lays the foundation for the study of the metamaterial structure in the traveling wave tube.

KEY WORDS: FWG-TWT, metamaterial, absorber

目 录

摘要................................................................................................................................................Ⅰ

Abstract..........................................................................................................................................Ⅱ

第一章 绪论...................................................................................................................................1

1.1 背景.................................................................................................................................1

1.2 行波管.............................................................................................................................1

1.2.1 行波管发展概况.................................................................................................1

1.2.2 行波管原理及结构.............................................................................................2

1.2.3 折叠波导行波管.................................................................................................3

1.3 人工超材料.....................................................................................................................4

1.3.1 超材料发展概况.................................................................................................4

1.3.2 超材料吸波器.....................................................................................................5

1.4 本文主要工作.................................................................................................................6

第二章 超材料吸波器设计的理论基础.......................................................................................8

2.1 吸波特性.........................................................................................................................8

2.2 阻抗匹配.........................................................................................................................8

2.3 等效参数.........................................................................................................................9

2.4 本章小结.......................................................................................................................12

第三章 超材料衰减结构.............................................................................................................14

3.1 吸波器单元模型...........................................................................................................14

3.2 适配矩形波导的结构研究...........................................................................................15

3.2.1 介质层厚度对吸波性能的影响.......................................................................15

3.2.2 谐振环位置对吸波性能的影响.......................................................................16

3.2.3 谐振环开口尺寸对吸波性能的影响...............................................................16

3.2.4 谐振环线宽对吸波性能的影响.......................................................................17

3.3 本章小结.......................................................................................................................17

第四章 加载超材料吸波结构的折叠波导慢波结构性能分析.................................................19

4.1 折叠波导单元模型.......................................................................................................19

4.2 色散特性及耦合阻抗...................................................................................................19

4.3 工作电压选择...............................................................................................................20

4.4 PIC性能分析................................................................................................................21

4.5 本章小结.......................................................................................................................25

第五章 总结及展望.....................................................................................................................27

5.1 工作总结.......................................................................................................................27

5.2 展望...............................................................................................................................28

参考文献.......................................................................................................................................29

致谢...............................................................................................................................................30

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