双频段太赫兹超材料吸波体的设计及传感特性研究
Design of a Dual-Band Terahertz Metamaterial Absorber and Sensing Research
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摘要: 提出了一种基于不同半径金属圆环加载于介质层的新型太赫兹超材料吸波体,实现了双频段的完美吸收和偏振不敏感性,且具备宽角度入射时可达到良好吸收的性能。仿真结果表明,该吸波体在f1 = 2.335 THz 和f2 = 4.215 THz 均可实现完美吸收,吸收率高达99. 99%;当入射角度达到70°时吸收率仍能保持80%以上。进一步分析可知,两个吸收峰分别由半径不同的金属圆环谐振产生,故而吸收峰的谐振频率可以通过调节圆环的半径进行单独调制。此外,还研究了该吸波体在介电传感和厚度传感两方面的应用。结果表明该吸波体对介电常数小于10的物质具有较好的传感性能,且吸收峰f2 的灵敏度较高;而应用于厚度传感时,吸收峰f1 的稳定性更适宜。研究结论对于设计新型超材料吸波体及其在传感中的应用具有重要意义。Abstract: A novel terahertz perfect metamaterial absorber based on metal rings with different radii loaded on the dielectric layer is presented in this paper, which realizes dual-band absorption and polarization insensitivity, and has the good absorption performance at wide angle incidence. Simulation results show that the perfect absorption of the absorber is achieved at both f1 =2.335 THz and f2 =4.215 THz, with the absorption rate is as high as 99. 99%; when the incident angle reaches 70°, the absorption rate can always be maintained above 80%. Further analysis shows that the two absorption peaks are generated by the resonance of metal rings with different radius, which can be modulated individually by adjusting the radius of the ring. In addition, the applications of this absorber in dielectric sensing and thickness sensing is also discussed. It can be seen from the research results that the absorber has better sensing performance for objects with a dielectric constant less than 10, and the sensitivity of the absorption peak f2 is higher. When applied to thickness sensing, the stable performance of the absorption peak f1 is more suitable. The above research conclusions are of great significance for the design of new metamaterial absorbers and their applications in sensing.