TE模式下子域二阶精度FDTD算法

Second-order accurate FDTD technique with subgridding modeling in TE mode

提出了一种子域时域有限差分法(FDTD)的改进算法,针对研究区域介质填充不均匀的情况,在不同介质区域粗细网格合理划分的同时,应用介质交界面处二阶精度FDTD算法,计算交界面上切向电场.从积分形式麦克斯韦方程出发,通过非均匀网格的建立和辅助磁场的引入,实现介质交界面上切向电场的二阶精度.与传统的子域算法相比,改进算法在不增加计算量、计算时间和编程复杂度的前提下有效地提高了计算精度.最后对几种波导结构进行了模拟,结果表明改进算法的计算精度明显高于传统的子域算法和常规的FDTD算法.

A modified subgridding finite difference time domain method （FDTD） is proposed. For the study of the computational domain filled with different dielectric materials and the reasonable division of coarse and fine grids in different dielectric regions, the second-order accurate FDTD technique at the dielectric interface is employed to analyze the tangential electric field components at the interface. Based on Maxwell＇s equations in integral form, the second-order accuracy of the tangential electric fields at the dielectric interface is obtained by the establishment of the nonuniform grids and the introduction of the auxiliary magnetic fields. The overall computational accuracy of the modified subgridding algorithm can be improved effectively, without additional computational capacity, consumed time and complexity in programming. Finally, the numerical simulations for some waveguide structures are carried out to validate the better accuracy of the method proposed in this paper than that of the traditional subgridding method and the standard FDTD method.