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 i