基于平行金属线的太赫兹准全向超材料吸波体  

Parallel metal-wire quasi-omnidirectional terahertz metamaterial absorber

作　　者：顾超[1] 屈绍波[1,2] 裴志斌[1] 徐卓[2] 林宝勤[1] 马华[1] 柏鹏[3] 彭卫东[3] 周航[1] 

机构地区：[1]空军工程大学理学院,西安710051 [2]西安交通大学电子陶瓷与器件教育部重点实验室,西安710049 [3]空军工程大学综合电子信息系统研究中心,西安710051

出　　处：《中国科学：物理学、力学、天文学》2011年第3期280-285,共6页Scientia Sinica Physica,Mechanica & Astronomica

基　　金：国家自然科学基金(批准号:60871027;60901029;61071058);国家重点基础研究发展计划(编号:2009CB623306);陕西省电子信息系统综合集成重点实验室基金(编号:200905A)资助项目

摘　　要：该文基于平行金属线设计了一种具有准全向吸波特性的太赫兹超材料吸波体,其准全向吸波特性是通过提高超材料的结构对称性实现的.理论和仿真结果表明:随着超材料结构对称性的提高,超材料吸波体的极化敏感度逐渐降低直至达到任意极化吸波.仿真的不同入射角下的吸收率与表面电流分布表明:平行于介质基板的磁场分量在平行金属线之间激发的反向平行电流导致了结构的电磁谐振,因而在极宽的入射角下该超材料吸波体仍能对电磁波进行高效吸收.提取的等效阻抗实部表明:可以通过调节基板两侧金属线的尺寸,来实现吸收频率处超材料吸波体一侧与自由空间近似阻抗匹配,另一侧与自由空间阻抗不匹配,从而使得反射和传输同时最小、吸收最高.仿真的能量损耗分布表明:该吸波体的强吸收主要源于基板的介质损耗.该太赫兹吸波体可能在爆炸物探测和材料识别等领域具有广泛的应用.We report the design of a quasi-omnidirectional terahertz metamaterial absorber based on parallel metal wires.The quasi-omnidirectional property of our absorber can be realized by improving the symmetry of the metamaterial cell.Both theoretical and simulated results show that the polarization sensitivity of our absorber can be weaken up to be polarization-insensitive by improving the symmetry of metamaterial cell.Simulated absorbance values under different incidence angles and the distribution of surface currents show that the electromagnetic resonance roots in antiparallel currents excitated by the magnetic field component parallel to the substrate.So under a wide angle of incidence our absorber could effectively absorb electromagnetic waves.The retrieved real parts of impedance show that the impedance of our absorber could be tuned to approximatively match the impedance of free space on the one side and not match to the impedance of free space on the other side.This design could realize the minimal reflectance,the minimal transmission and the highest absorbance at the absorption frequency.The distribution of power losses shows that the strong absorption is mainly due to dielectric losses of the substrate.This metamaterial absorber may have applications in detection of explosives and material characterization.

关 键 词：超材料吸波体 太赫兹 准全向吸波 

分 类 号：TB34[一般工业技术—材料科学与工程]