二维非正交坐标系下FDTD方法的数值色散特性

本文详细讨论了二维非正交坐标系下FDTD方法的色散特性，导出了其数值色散方程。理论计算结果表明，非正交FDTD方法的空间色散与网络尺寸、网络内角、波传播方向有密切关系。同时指出，在应用非正交FDTD方法解决有关时域电磁问题时，网格的部分应分量选取网格边长相接近，夹角接近90的情况以减少此方法的数值色散。

Numerical Dispersion of Nonorthogonal FDTD Algorithm in 2-D Obliquely Cartesian Coordinates

In this paper the numerical dispersion characteristics of nonorthogonal FDTD algorithm in two- dimensional oblique Cartesian coordinates are discussed in detail. The numerical dispersion equation is derived and the dispersion curves in a varity of cases are obtained. The theoretical results show that the dispersion effects are related tightly with the grid sizes, the direction of the wave propagation and the angles between two edges of each grid. When the nonorthogonal FDTD algorithm is used in practice to resolve electromagnetic problems in time domain, in order to reduce the numerical dispersion effects the grids in the computational space should be chosen to have as closely similar shapes and same sizes as possible.