FDTD.m 程序包括程序相关变量的定义，网格的尺寸的划分，激励源的设置及基于FDTD的圆柱谐振腔迭代分析。其中通过改变空间离散度dr和采样点个数nmax，进行分析得出结论；且空间步长dt与dr有关，可得出空间步长对结果影响。-FDTD.m program includes the definition of program-related variables, set the meshing of size, the excitation source and the FDTD-based iterative analysis of cylindrical cavity. By changing the space in which the number of discrete sampling points of the dr and nmax, the conclusions drawn　the analysis　and space step dt and dr related space step can be drawn　the impact on the results.