为了高效精确地求解端接任意负载的传输线结构电磁瞬态响应，该文提出了一种基于分裂时间步技术的Crank-Nicolson (CN)-FDTD方法，通过理论分析证明了该方法具有无条件稳定特性。与混合单端口等效模型相结合，有效地将传输线系统分解为分布参数子系统与集总电路子系统，采用改进节点分析法(Modified Nodal Analysis, MNA)能够快速求解复杂终端电路网络。与以往瞬态分析方法相比，该方法时间步长的选取不受稳定条件的限制，且通过采用精细子时间步技术极大地削减了因大时间步长引入的色散误差。利用该方法计算双导体传输系统的电磁暂态响应，计算结果表明该算法具有很好的稳定性，在保证数值精度的基础上有效地提高了计算效率。
A novel Crank-Nicolson (CN)-FDTD method based on the split-step scheme is proposed in this paper, so as to calculate the electromagnetic transients in transmission line with complex circuit terminals accurately and efficiently. An analytical proof of unconditional stability of the method is provided. Combined with the hybrid one-port equivalent model, the transmission system is decomposed into lumped and distributed portions independently. It can solve the time response of the complex circuit networks by utilizing the Modified Nodal Analysis (MNA) method. Unlike the former methods, the maximum time step size is not limited by the restriction of Courant-Friedrichs-Lewy (CFL) stability constraint. In addition, the dispersion errors can be reduced by the precision sub-time-step scheme. The method is utilized to the transient analysis of the single transmission line. The results show that the proposed method provides higher efficiency and good stability under the same precision level.