利用等效电路模型,用仿真模拟软件对空气环金属阵列的透射特性进行仿真, 得出空气环金属阵列的几何参数对透射峰的影响规律: 一种透射峰随着空气环金属阵列空气环外半径、内半径的增大发生红移, 金属层厚度对该透射峰的影响可忽略；另一种透射峰随着空气环金属阵列金属层厚度和空气环外半径、内半径的增大发生红移.根据透射峰处金属表面的电流分布, 用磁谐振效应理论和导模共振理论对透射峰的产生做出解释；基于磁极化理论建立等效电路模型, 研究了空气环金属阵列的几何参数对磁谐振峰位置的影响,即: 改变阵列的几何参可导致等效电容、电感的改变, 从而促使磁谐振峰的移动.等效电路与模拟软件仿真的结果对比表明, 所建立的等效电路模型对太赫兹滤波器的结构设计和性能分析具有重要参考价值.

To design high performance terahertz filters, the optical properties of the subwavelength metallic coaxial aperture arrays were investigated. The characteristics of transmission spectra were simulated by the electromagnetic field simulation software. With the change of the geometrical parameters of the structure, two different transmission peaks appeared. One transmission peak redshifts with the increase of the outer radius or the inner radius of the air annulation, and the influence of the thickness on this peak can be neglected. Another transmission peak moves toward long wavelength with the increase of the out radius of the annulation, or the inner radius, or the thickness. This paper also provides an explanation of the phenomena by means of the localized magnetic polaritons and guided mode resonance based on the distribution of the surface current. According to the magnetic plasmon resonance, the equivalent circuit model of the metamaterial for the incidences of the transverse electromagnetic wave were set up, the effects of geometric parameters and lateral displacement on the resonance conditions were studied by this model. The variation of the array geometry parameters changes the capacitance and inductance of the equivalent circuit, which leads to the shift of the magnetic resonance peak. Comparison of the result of simulation with that of the equivalent circuit model shows that the equivalent circuit models could be useful for structure design and performance analysis of the metamaterial terahertz filters.