A nearly exact second-order finite-difference time-domain wave propagation algorithm on a coarse grid

摘要: We introduce a new second‐order finite‐difference time‐domain (FDTD) algorithm to solve the wave equation on coarse grid with solution error less than 10−4 that of conventional one. Although computational load per time step is greater, it more offset by large reduction in number points needed, while maintaining high accuracy, as well iterations. In addition, boundaries can be accurately characterized at subgrid level. This based Laplacian nearly isotropic respect propagation direction. optimum performance achieved fixed frequency, accuracy still much higher FDTD over ‘‘moderate’’ bandwidths.