基于柔性超材料的毫米波多频吸波器

发布时间：2018-04-29 14:33

本文选题：超材料 + 吸波器　；参考：《中北大学》2017年硕士论文

【摘要】：电磁超材料不仅代表了基于人工复合亚波长微结构的新型功能材料,更意味着定制化调控电磁响应,任意裁剪电磁波的逆向设计思维,即需要什么样的电磁响应,设计相应的微结构。其通常具有自然界中常规材料所不具备的一些奇特电磁特性,在电磁器件、生化检测、电磁隐身与防护等领域具有广泛的应用前景。通过合理设计超材料的微结构形状、尺寸、材料、分布等,使其整体波阻抗等于自由空间,达到完美匹配,进而实现对特定频段电磁波的完美吸收。现有的超材料吸波器的吸波频带的个数不大于其谐振器的个数,增加吸波器的吸波频带必须适当增加谐振器的个数,势必会增加吸波器的设计和加工难度,本文利用数量更少的谐振器获取更多的谐振频带和更好的吸波性能。本文首先综合应用理论分析和数值模拟相结合的方法,对基于周期性双方环谐振器的吸波器在毫米波频段的多频吸收机制进行了系统研究。基于吸波理论和散射理论设计了三款基于周期性“回”字型微结构的超材料多频吸波器,运用全波分析法计算TE和TM偏振波垂直入射时三款吸波器的吸波率曲线,发现通过调节尺寸,双方环谐振器可以实现双频、三频、四频谐振,并根据强谐振时双方环及其内外环的表面电场分布探索多频吸波的物理机制。并逐个分析尺寸、材料和入射波等参数对吸波性能的具体影响。接着,设计了基于RZJ-304正性光刻胶的UV-LIGA工艺和磁控溅射技术的在环氧树脂板上加工周期性双方环“三明治”式吸波器的便捷工艺,详细探讨了整套工艺的工艺流程,参数影响和注意事项,并用对制备的三款样片进行形貌表征以证实工艺的可行性。其次,详细地介绍了常用的三种测试方案的测试步骤以及注意事项。本文折中选择THz-TDS测试方法,发现TDS1008实测三款样片得到吸波率曲线在低频段与电磁仿真结果大致重合,但在高频段时与数值仿真结果有些许出入,吸波率的实测值较仿真值有轻微降低。最后,通过微结构形貌表征对这些偏差的可能来源进行了合理剖析。最后,对论文的主要工作和结论及其创新之处进行总结归纳,并对研究的不足和超材料吸波器下一步的发展进行总结和展望。
[Abstract]:Electromagnetic supermaterial not only represents a new functional material based on artificial composite subwavelength microstructure, but also means customizing the control of electromagnetic response, tailoring the inverse design thinking of electromagnetic wave, that is, what kind of electromagnetic response is needed. The corresponding microstructures are designed. It usually has some peculiar electromagnetic properties which are not possessed by conventional materials in nature. It has a wide application prospect in electromagnetic devices, biochemical detection, electromagnetic stealth and protection and so on. By reasonably designing the microstructure shape, size, material and distribution of the metamaterials, the integral wave impedance is equal to the free space, and the perfect matching is achieved, and the perfect absorption of the electromagnetic waves in the specific frequency band is realized. The number of absorbing frequency bands of existing metamaterial absorbers is not larger than the number of resonators. To increase the frequency band of absorbers, it is necessary to increase the number of resonators properly, which will inevitably increase the difficulty of designing and processing the absorbers. In this paper, a smaller number of resonators are used to obtain more resonant frequency bands and better absorbing performance. In this paper, the multi-frequency absorption mechanism of periodic two-ring resonator in millimeter-wave band is systematically studied by combining theoretical analysis with numerical simulation. Based on absorbing theory and scattering theory, three kinds of supermaterial multi-frequency absorbers based on periodic "echo" microstructures are designed. The absorptivity curves of three kinds of absorbers when te and TM polarized waves are perpendicular to incident are calculated by using full wave analysis method. It is found that the double frequency, three frequency and four frequency resonance can be realized by adjusting the size of the double ring resonator, and the physical mechanism of the multi-frequency wave absorption can be explored according to the surface electric field distribution of the two rings and their inner and outer rings when the resonance is strong. The effects of parameters such as size, material and incident wave on the absorbing performance are analyzed one by one. Then, the UV-LIGA process based on RZJ-304 positive photoresist and the convenient technology of magnetron sputtering for processing periodic double ring sandwich type wave absorber on epoxy resin plate are designed, and the process flow of the whole process is discussed in detail. The influence of the parameters and the points for attention were discussed. The three samples were characterized by morphologies to verify the feasibility of the process. Secondly, the test steps and points for attention of the three commonly used test schemes are introduced in detail. In this paper, the THz-TDS test method is chosen, and it is found that the absorbing rate curve obtained by TDS1008 is approximately in agreement with the electromagnetic simulation results in the low frequency band, but it is slightly different from the numerical simulation results in the high frequency band. The measured value of absorbing rate is slightly lower than that of simulation. Finally, the possible sources of these deviations are analyzed by means of microstructure and morphology characterization. Finally, the main work, conclusions and innovations of the paper are summarized and summarized, and the shortcomings of the research and the next development of the metamaterial absorber are summarized and prospected.
【学位授予单位】：中北大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TB34

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