基于超材料结构的电磁波吸收特性研究

发布时间：2018-01-06 11:06

本文关键词：基于超材料结构的电磁波吸收特性研究　出处：《长春理工大学》2017年博士论文　论文类型：学位论文

【摘要】：超材料作为一种新型的人工材料,可以看成是由金属和电介质周期性排列的单元结构所组成,它具有自然界中常规材料所没有的许多奇特物理性质,打破了传统材料设计思想的局限性,大大提高了材料综合性能。目前,超材料已经发展成为了一个涉及物理学、材料学、化学等多个学科的交叉前沿学科。而基于超材料的电磁吸波器具有许多传统吸波器所不具备的优势,如完美吸收、超薄、工作频率可调以及结构电磁参数可设计等,可应用于传感器、探测器、太阳能光伏等诸多领域。近年来,基于超材料的电磁吸波器已成为微纳光子学领域的的研究热点之一。本论文从超材料的吸波原理出发,针对基于超材料的电磁吸波器展开了设计及理论模拟研究。利用时域有限差分算法,采用FDTD Solutions软件计算了多种超材料吸波器的电磁吸收特性。所设计及模拟电磁吸波器的工作频带包括单频带、双频带、宽频带等,其工作波长涵盖了可见光、近/中红外以及太赫兹波段。采用阻抗匹配理论分析了吸波器的电磁波吸收机理,并讨论了超材料结构尺寸以及材料属性对电磁波吸收效率的影响,同时进一步讨论了TM和TE模式下电磁波入射角度对超材料电磁吸收的影响。本论文的主要工作内容如下:首先,设计并模拟研究了一种基于金属光栅结构的窄频带电磁吸波器,该器件在600~1300 nm工作波段范围内可实现不同频带的吸收。基于该结构的电磁场以及能流密度分布特点,详细分析了其电磁波吸收机制。研究发现,当光栅宽度小于250 nm时,该电磁吸波器可表现为单频带近100%的完美吸收,但是当金属宽度约为360 nm时,器件则表现为双频带吸收。而且,通过调节超材料的金属层以及电介质层的厚度均可实现其共振吸收波长的调谐。因此,可以根据实际需要设计单元结构中的相关参数。由于设计的光栅结构对于电磁波偏振模式具有敏感性,为了克服以上光栅结构电磁吸波器的这一弊端,我们进一步设计了基于圆柱体结构的电磁吸波器,该器件具有偏振不敏感的特点,可实现可见光范围内的双频带吸收。该两类电磁吸波器的共同特点为具有窄带电磁波高吸收性能。接下来,论文设计并模拟研究了一种基于金字塔形阵列结构的宽频带电磁吸波器。金字塔形结构单元由金属铝和电介质锗材料交错堆叠形成的多层结构组成,其实现了工作波段0.2~3.6μm范围内的超宽带电磁波吸收。论文采用表面等离子体共振和慢波模理论研究了该吸波器的电磁波吸收机制,解释了结构中电磁场的分布特点。研究表明该器件具有高吸收、宽角度、偏振不敏感、方位角不敏感等诸多优点,在太阳能光伏、热发射器等领域具有重要应用前景。由于锥形多层纳米结构在加工实现时具有较大的困难,为简化单元结构,设计了基于金属-电介质-金属(MDM)结构阵列的二维电磁吸波器,其在约600~1300 nm的波带范围内,吸收率高于80%的谱线带宽约为300 nm。进一步,分析了该简化结构的电磁波吸收机理,讨论了结构参数对电磁波吸收的影响。该工作可为太阳能光伏等领域器件的应用提供理论基础。由于太赫兹波段为新兴的研究热点以及有着重要的应用,我们将所研究吸波器的工作波段拓展到了太赫兹波段。本文设计并模拟研究了窄频带以及宽频带的三种超材料太赫兹吸波器,分析太赫兹频段的电磁波吸收问题。对于窄频段太赫兹吸波器,本文设计相对简单的金属薄片结构来实现其共振吸收,并采用等效LC电路模型来分析结构参数与共振频率之间的关系。该结构具有简单、可调谐、易加工的特点,有望应用于探测器等领域。根据宽带吸收实现方法的不同,本文分别设计并模拟研究了基于金属层叠结构以及金属共面结构的太赫兹吸波器。发现通过不同尺寸金属单元所对应的吸收峰的叠加,可实现宽频带的太赫兹吸收。本文结合共振频率处电磁谐振的特点以及金属表面电流分布,解释了超材料太赫兹吸波器的吸收原理,并分析了结构参数对吸收产生的影响。本文获得的宽频带太赫兹吸波器的研究成果,对其在电磁隐身、宽带通信、安全检测等领域的应用提供了理论依据。
[Abstract]:Super material as a new type of artificial materials, can be viewed as the unit structure is arranged by metal and dielectric periodic component, it has many unique physical properties of conventional materials in nature are not, breaking the limitations of traditional material design, greatly improve the comprehensive performance of the material. The material has become super one involves physics, material science, cross frontier disciplines of chemistry. The metamaterial absorber has many traditional absorbers do not have the advantage, such as perfect absorption, ultra-thin, adjustable working frequency and electromagnetic parameters can be designed, which can be applied to the sensor, the detector solar photovoltaic, and other fields. In recent years, electromagnetic metamaterial absorber has become one of the hot research on micro nano photonics field. In this thesis, based on principle of super absorbing materials, The absorber launched a simulation study on the theory and design of electromagnetic metamaterials based on the FDTD algorithm, a variety of super absorbing material for electromagnetic wave absorption properties were calculated by FDTD Solutions software. The design and Simulation of electromagnetic absorber working frequency band including single band, dual band, broadband etc. the work covers the wavelength of visible light, near infrared and terahertz /. The impedance matching theory to analyze the absorption of electromagnetic wave absorption mechanism of the filter, and the effects of metamaterial structure size and material properties on absorption efficiency of electromagnetic waves, and the effect of TM and TE mode electromagnetic wave incident angle of metamaterials the electromagnetic absorption is also discussed. The main contents of this dissertation are as follows: firstly, the design and Simulation of a metal grating structure based on narrow-band electromagnetic wave absorbing device, the device in the 600~1300 nm wave Range can be realized in different frequency band absorption. The structure of the electromagnetic field and energy flow density distribution based on a detailed analysis of the electromagnetic wave absorption mechanism. The study found that when the grating width is less than 250 nm, the electromagnetic absorber can be expressed as the perfect single band nearly 100% of the absorption, but when the width of metal for 360 nm, the device is a dual band absorption. Moreover, by adjusting the metamaterial metal layer and the dielectric layer thickness can achieve the resonance absorption wavelength. Therefore, according to the actual needs of the relevant design parameters of unit structure. The structure design of the grating is sensitive to the electromagnetic wave polarization mode, in order to this disadvantage above grating structure electromagnetic wave absorption device, we design the electromagnetic absorber cylinder based on the structure, the device has the characteristics of polarization insensitive, visible light can be realized Dual frequency range. The absorption band of two electromagnetic wave absorbing device has the common characteristics of electromagnetic wave absorption performance for narrowband. Next, on a broadband Pyramid shaped array structure based on electromagnetic wave absorbing device is designed and simulated. The Pyramid structure unit is composed of metal dielectric and aluminum germanium staggered multilayer structure stack the composition, the ultra wideband electromagnetic wave absorption band 0.2~3.6 m range. The surface plasmon resonance and slow wave mode theory of electromagnetic wave absorption mechanism of the absorber of the thesis, explains the distribution of electromagnetic field in the structure. The research shows that this device has high absorption, wide angle. Polarization insensitive, azimuth sensitivity and many other advantages, in the solar photovoltaic thermal emitter has important application prospect in fields. Because of the taper multilayer nanostructures in the processing has great implementation Difficult to simplify the unit structure, design of metal dielectric metal (MDM) structure based on 2D electromagnetic array absorber, which at about 600~1300 nm waveband range, the absorption rate is higher than the spectral bandwidth of 80% is about 300 nm. further, analyzed the electromagnetic wave absorption mechanism of the simplified structure, influence the structure parameters of the electromagnetic wave absorption is discussed. The work can provide a theoretical basis for the application of solar photovoltaic devices and other fields. As a new research hotspot for terahertz and has an important application, we will study the suction filter band extended to terahertz band. The narrow band and wide band three a metamaterial absorber is designed and simulation analysis of electromagnetic wave absorption in THz band. For narrowband terahertz wave absorbing device, sheet metal structure design in this paper is relatively simple to achieve the total The vibration absorption, and to analyze the relationship between the structure parameters and the resonant frequency of the equivalent circuit model of LC. The structure is simple, tunable, easy processing characteristics, is expected to be applied to the detector and other fields. According to the different methods of realizing broadband absorption, this paper design and Simulation Research of the absorber metal laminated structure and terahertz metal coplanar structure based on different size. Found by metal element corresponding to the absorption peak of the overlay, can realize broadband terahertz absorption. Based on the resonant frequency of electromagnetic resonant characteristics and metal surface current distribution, explain the absorption principle of metamaterial absorber, and analyzes the influence of structure parameters on absorption the broadband. The obtained research results with Terahertz Absorption wave, the electromagnetic stealth, broadband communication, provides the theoretical basis application security detection etc. According to.

【学位授予单位】：长春理工大学
【学位级别】：博士
【学位授予年份】：2017
【分类号】：TB34;O441

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