传输线端接复杂电路的电磁耦合时域分析方法

该文基于时域有限差分(FDTD)方法和传输线方程，结合Ngspice软件，提出一种高效的时域混合算法，能够快速模拟空间电磁场作用传输线端接复杂电路的电磁耦合问题。该算法的优势在于实现了空间电磁场辐射与端接复杂电路瞬态响应的协同计算，且避免了对传输线和复杂电路结构的直接建模。首先，将复杂电路通过传输线的特性阻抗进行等效，采用FDTD方法结合传输线方程，求解得到特性阻抗上的入射电流响应。然后，在每个时间步上，将该电流引入复杂电路作为激励源，联合电路模型建立网表文件。最后，使用Ngspice软件读取网表文件，并仿真得到电路各元件上的瞬态响应。通过相应计算实例的数值模拟，与电磁场仿真软件CST的计算结果以及耗用内存和时间进行对比，验证了算法的正确性和高效性。

Time Domain Analysis Method for the Coupling Problem of Transmission Lines Terminated with Complex Circuits

An efficient time domain hybrid method is presented consisting of Finite-Difference Time-Domain (FDTD) method, Transmission Line (TL) equations, and Ngspice software to be well applied to the coupling analysis of transmission lines terminated with complex circuits excited by space electromagnetic fields. The significant features of this presented method are that it can realize the co-calculation of electromagnetic field radiation and transient responses on the lines and complex circuits, and avoid modeling the structures of transmission lines and circuits directly. Firstly, the complex circuits are replaced by the characteristic impedances of corresponding transmission lines, and then the FDTD method combined with TL equations is adopted to solve the incident currents on these impedances. Secondly, the incident currents are introduced into the complex circuits as excitation sources at each time step of FDTD simulation, which are combined with the circuits to form the netlist files. Finally, transient responses on the elements of circuits are obtained by using the Ngspice software. Numerical simulations are utilized to verify the correctness and efficiency of this hybrid method by comparing with the electromagnetic software CST in simulation results and consumptions of memories and computation time.