该程序利用有限时域差分法在线激励源和PML吸收边界条件下模拟了含一圆柱介质的空间内的电磁场分布，计算了圆柱介质内某一频率的电磁场分布和空间内某一点处电场的幅度-时间响应曲线。(The program uses the finite difference time domain method to simulate the electromagnetic fields distribution at a certain frequency in a cylindrical medium space