三层单负材料结构中电磁波模分析

摘要

The modes in a three-layered structure made of single-negative materials have been investigated. For the propagation mode, the tunneling mode can be formed in the structure. When tunneling mode appears the variations of electric field distribution and the transmission with incident angle are studied. We find that there appear two new localized modes when the thickness of the middle layer changes. The frequency interval of the two localized modes can be increased by decreasing the thickness of the middle layer. For the guided mode, the electromagnetic wave is evanescent in semi-infinite vacuum which is on the both sides of the structure. We have analyzed the existence condition of its electromagnetic mode, that is, the dispersion relation. The result shows that a strong local field appears in the interface of the material.%本文分析了由负介电常数材料和负磁导率材料交替排列组成的一维三层结构中的电磁波模式，包括传播模及波导模．传播模对应于入射的行波模，着重研究了发生共振隧穿时场分布和透射谱随入射角度的变化关系，发现改变结构参数时共振隧穿频率会劈裂成两个，且这两个隧穿模的频率间距随着中间层厚度的减小而逐渐加大．波导模是指在结构两边的半无限真空中以倏逝场形式存在的电磁模式，分析了它的存在条件即色散关系，发现这种模在材料的交界面处会出现较强的局域场．