亚波长金属线阵中一维时间反演电磁波的聚焦机理研究

基于周期金属线阵的等效电介质模型, 并使用传输线理论方法, 得到了金属线阵中时间反演电磁波的解析表达式. 接着, 在等效电介质模型的适用范围内, 讨论了金属线半径、金属线阵周期、金属线阵周期数对时间反演电磁波聚焦的影响. 从而在理论上证实, 这种结构可以实现远场时间反演电磁波聚焦, 同时, 也为时间反演技术提供了工程参考.     

Hybrid sub-gridding ADE–FDTD method of modeling periodic metallic nanoparticle arrays

In this paper, a modified sub-gridding scheme that hybridizes the conventional finite-difference time-domain(FDTD)method and the unconditionally stable locally one-dimensional(LOD) FDTD is developed for analyzing the periodic metallic nanoparticle arrays. The dispersion of the metal, caused by the evanescent wave propagating along the metal-dielectric interface, is expressed by the Drude model and solved with a generalized auxiliary differential equation(ADE) technique.In the sub-gridding scheme, the ADE–FDTD is applied to the global coarse grids while the ADE–LOD–FDTD is applied to the local fine grids. The time step sizes in the fine-grid region and coarse-grid region can be synchronized, and thus obviating the temporal interpolation of the fields in the time-marching process. Numerical examples about extraordinary optical transmission through the periodic metallic nanoparticle array are provided to show the accuracy and efficiency of the proposed method.     

The determination of the relative permittivity of periodic stratified media based on the iterative time-reversal method

In this paper, we present a new method to determine the relative permittivity of periodic stratified media using the iterative time-reversal method. Based on transmission line theory, the focal peak value of iterative time-reversal electro- magnetic waves, which contain information about the periodic stratified medium, is computed in pulse-echo mode. Using the relationship between the focal peak value and the relative permittivity of the periodic stratified medium, the relative permittivity can be obtained by measuring the focal peak value. Numerical simulations are conducted, and the results demonstrate the feasibility of the proposed approach to the measurement of the relative permittivity of a periodic stratified medium.     

基于远场时间反演的亚波长天线阵列研究

基于远场时间反演, 从信号处理角度对亚波长阵列的超分辨率聚焦特性进行了理论分析. 提出了一种新型的微结构刻蚀亚波长阵列, 通过时间反演聚焦实验表明, 该阵列具有远场超分辨聚焦特性, 各单元间信道相互独立. 将这种亚波长阵列应用在时间反演镜天线上, 通过实验验证了可以获得更好的超分辨率聚焦效果. 所提出的亚波长天线阵列对多天线超宽带无线通信具有潜在的应用价值. 关键词： 时间反演 亚波长 天线阵列 超分辨率