基于超材料的偏振不敏感太赫兹宽带吸波体设计  

Design of a polarization-insensitive and broadband terahertz absorber using metamaterials

作　　者：邹涛波 胡放荣[1] 肖靖[2] 张隆辉[1] 刘芳[1] 陈涛[1] 牛军浩[1] 熊显名[1] 

机构地区：[1]桂林电子科技大学电子工程与自动化学院,桂林541004 [2]空军勤务学院,徐州221000

出　　处：《物理学报》2014年第17期342-350,共9页Acta Physica Sinica

基　　金：国家自然科学基金(批准号:61265005);广西信息科学实验中心项目(批准号:20130101);广西自动检测技术与仪器重点实验室项目(批准号:YQ14114);广西研究生教育创新计划资助项目(批准号:YCSZ2014141);桂林电子科技大学创新团队项目资助的课题~~

摘　　要：本文设计了一种基于超材料的偏振不敏感太赫兹宽带吸波体.吸波体包含两层金属和一层中间介质,表面金属层每一个周期单元由五种尺寸接近的金属块按照相邻不同的规律排列成5×5的方形阵列.各种尺寸金属块分别产生单峰谐振吸收,五个谐振吸收峰相互靠近从而产生宽带吸收.通过研究吸波体表面电流和电场z分量分布情况可知,入射太赫兹能量的吸收主要是由y方向上电场引起的电偶极子振荡和z方向上磁场引起的磁极化产生,而且金属层的欧姆损耗起主要作用.仿真结果表明,吸波体吸收率在80%以上的带宽约为1.2 THz,最高吸收率可达98.7%,半峰全宽(FWHM)为1.6 THz,该宽带吸波体的厚度约为中心波长的二十分之一,对偏振方向不敏感,且能实现大角度吸收,在太赫兹频段的电磁隐身、测辐射热探测器以及宽带通信等领域有潜在的应用价值.A polarization-insensitive and broadband terahertz （THz） absorber based on metamaterial （MM） is presented. The absorber consists of two layers of metal and a single layer of medium. Each periodic cell of the upper metallic layer consists of five different sizes of metal patches which form a square array of 5×5. In the array, the size of each metal patch is different from that of its adjacent one, and each size of the metal patch generates a single resonance absorption peak. The broadband absorption is actually produced by the overlapping of five adjacent resonance absorption peaks. By studying the distribution of the surface current and the z-component of electric field, it is easy to know that the energy of the incident THz wave is absorbed by two factors： one is the electric dipole oscillation caused by the electric field in the y direction, and the other is the magnetic polariton caused by the magnetic field in the z direction. And the ohmic loss of metal layers plays a major role on the absorption of the absorber. Simulation results show that the bandwidth achieves 1.2 THz for the absorption beyond 80%, and the maximum absorption is up to 98.7%. It＇s full width at half maximum （FWHM） is 1.6 THz, and the thickness of the broadband absorber is only about one twentieth of the center wavelength. In addition, the absorber is insensitive to the polarization and has a wide-angle feature, and the potential applications of the absorber are electromagnetic stealth, THz thermal radiation detectors, and THz communication.

关 键 词：超材料 太赫兹吸波体 偏振不敏感 宽带吸收 

分 类 号：O441[理学—电磁学]