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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.
In this paper, a kind of THz metamaterial absorber with quasi-omnidirectional wave absorbing property is designed based on parallel metal lines. The quasi-omni-directional wave absorbing property is achieved by increasing the structural symmetry of metamaterials. Theory and Simulation The results show that with the increase of the symmetry of the metamaterial structure, the polarization sensitivity of the metamaterial absorber gradually decreases until it reaches any polarization absorption. The simulation of the absorption and surface current distribution at different angles of incidence shows that: parallel to The magnetic field component of the dielectric substrate excites the antiparallel currents between the parallel wires to cause the electromagnetic resonance of the structure so that the metamaterial absorber remains efficiently absorbing electromagnetic waves at very wide angles of incidence. The real part of the impedance shows that the impedance matching can be achieved by adjusting the dimensions of the metal lines on both sides of the substrate to achieve an approximate impedance matching on one side of the absorber with the free space at the absorption frequency and the free space impedance on the other side, At the same time, the maximum absorption is the highest.The simulated energy loss distribution shows that the strong absorption of the absorber is mainly due to the dielectric loss of the substrate.The THz absorber may be used in the detection of explosives Identifying fields and has wide application.