多频段宽角偏振不敏感超材料吸波器的研究
发布时间：2018-09-06 06:17
【摘要】：超材料作为一种人工复合结构或复合材料,具有自然界中存在的材料所不具备的某些特殊电磁性质,如负折射率、负群速度等,它在超分辨率成像、光学隐身、新型太阳能电池等领域具有重要的应用前景。超材料吸波器作为超材料的一个重要分支,最近近几年发展迅速,得到越来越多的关注。通过合理设计超材料的几何结构,使超材料吸波结构的表面阻抗与自由空间阻抗相匹配,可以实现对特定频段电磁波的完美吸收。超材料完美吸波器可以被应用于太赫兹成像,热辐射仪,有毒物质检测等诸多领域。本文主要应用计算机模拟和理论分析相结合的方法,对单频、多频超材料吸波器波段的吸收机制进行了系统研究,得到了几何参数和材料电磁参数对吸收率的影响规律。基于电磁波吸收理论和等效媒介理论等基本理论,研究了金属方形薄片超材料吸收器在中红外波段的吸收特性,通过调节其几何尺寸,能够实现单频完美吸收。结合等效电路模型分析该结构的谐振频率随几何参数的变化,并与仿真结果进行了比较。通过数值仿真计算的谐振频率和吸收率随几何参数的变化规律与通过等效电路模型推导的变化规律基本一致。通过分析超材料吸波器中电场模的分布解释其物理机制。研究了一种基于电谐振器结构的超材料吸波器的吸收特性,该吸收器在太赫兹波段可实现多频、偏振无关的、宽角度完美吸收。通过改变其几何参数,实现了该结构在中红外波段的多频完美吸收。并结合其电场模分布、能量损失密度分析其吸波机理。设计了一种多频超材料吸波器,该结构由一个电谐振器和金属基板组成,能在12-24 THz的中红外波段产生两个大于90%的吸收峰,通过分析其电场模的分布,解释其吸波机理。通过S参数反演法提取其等效参数,计算出其波阻抗。
[Abstract]:As a kind of artificial composite structure or composite material, metamaterials have some special electromagnetic properties, such as negative refractive index, negative group velocity and so on, which are not existed in nature. New solar cells and other fields have important application prospects. As an important branch of metamaterials, metamaterial absorbers have been developed rapidly in recent years and received more and more attention. By reasonably designing the geometrical structure of the supermaterial, the surface impedance of the supermaterial absorbing structure can be matched with the free space impedance, and the perfect absorption of the electromagnetic wave can be realized in the specific frequency band. Metamaterial perfect absorbers can be used in terahertz imaging, thermal radiometer, toxic substances detection and many other fields. In this paper, the absorption mechanism of single-frequency and multi-frequency supermaterial absorbers is systematically studied by means of computer simulation and theoretical analysis, and the influence of geometric and electromagnetic parameters on absorptivity is obtained. Based on the theory of electromagnetic wave absorption and equivalent medium theory, the absorption characteristics of metal square sheet supermaterial absorber in the mid-infrared band are studied. By adjusting its geometric size, the perfect absorption of single frequency can be realized. Based on the equivalent circuit model, the variation of resonant frequency with geometric parameters is analyzed and compared with the simulation results. The variation of resonance frequency and absorptivity with geometric parameters calculated by numerical simulation is basically consistent with that derived from equivalent circuit model. The physical mechanism is explained by analyzing the distribution of electric field modes in metamaterial absorbers. The absorption characteristics of a metamaterial absorber based on the structure of an electric resonator are studied. The absorber can achieve multi-frequency polarization-independent wide-angle perfect absorption in terahertz band. By changing its geometric parameters, the multi-frequency perfect absorption of the structure in the mid-infrared band is realized. The wave absorption mechanism is analyzed by combining the electric field mode distribution and energy loss density. A multi-frequency supermaterial absorber is designed. The structure consists of an electric resonator and a metal substrate. It can produce two absorption peaks of more than 90% in the mid-infrared band of 12-24 THz. The wave absorption mechanism is explained by analyzing the distribution of the electric field modes. The equivalent parameters are extracted by S-parameter inversion method, and the wave impedance is calculated.
【学位授予单位】：哈尔滨工业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TB33
本文编号：2225506
[Abstract]:As a kind of artificial composite structure or composite material, metamaterials have some special electromagnetic properties, such as negative refractive index, negative group velocity and so on, which are not existed in nature. New solar cells and other fields have important application prospects. As an important branch of metamaterials, metamaterial absorbers have been developed rapidly in recent years and received more and more attention. By reasonably designing the geometrical structure of the supermaterial, the surface impedance of the supermaterial absorbing structure can be matched with the free space impedance, and the perfect absorption of the electromagnetic wave can be realized in the specific frequency band. Metamaterial perfect absorbers can be used in terahertz imaging, thermal radiometer, toxic substances detection and many other fields. In this paper, the absorption mechanism of single-frequency and multi-frequency supermaterial absorbers is systematically studied by means of computer simulation and theoretical analysis, and the influence of geometric and electromagnetic parameters on absorptivity is obtained. Based on the theory of electromagnetic wave absorption and equivalent medium theory, the absorption characteristics of metal square sheet supermaterial absorber in the mid-infrared band are studied. By adjusting its geometric size, the perfect absorption of single frequency can be realized. Based on the equivalent circuit model, the variation of resonant frequency with geometric parameters is analyzed and compared with the simulation results. The variation of resonance frequency and absorptivity with geometric parameters calculated by numerical simulation is basically consistent with that derived from equivalent circuit model. The physical mechanism is explained by analyzing the distribution of electric field modes in metamaterial absorbers. The absorption characteristics of a metamaterial absorber based on the structure of an electric resonator are studied. The absorber can achieve multi-frequency polarization-independent wide-angle perfect absorption in terahertz band. By changing its geometric parameters, the multi-frequency perfect absorption of the structure in the mid-infrared band is realized. The wave absorption mechanism is analyzed by combining the electric field mode distribution and energy loss density. A multi-frequency supermaterial absorber is designed. The structure consists of an electric resonator and a metal substrate. It can produce two absorption peaks of more than 90% in the mid-infrared band of 12-24 THz. The wave absorption mechanism is explained by analyzing the distribution of the electric field modes. The equivalent parameters are extracted by S-parameter inversion method, and the wave impedance is calculated.
【学位授予单位】：哈尔滨工业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TB33
【参考文献】
相关期刊论文 前1条
1 顾超;屈绍波;裴志斌;徐卓;刘嘉;顾巍;;Multiband terahertz metamaterial absorber[J];Chinese Physics B;2011年01期
，本文编号：2225506
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