Crosstalk Analysis of Microstrip Lines Terminated with Complex Circuits via Time Domain Modeling Method

An novel time-domain hybrid method, proposed by integrating transmission line (TL) equations, finite-difference time-domain (FDTD) method, Substitution theorem, Norton’s theorem and NGSPICE software, is proposed for the crosstalk analysis of microstrip lines (MSLs) terminated with complex circuits. Firstly, the overall structure of microstrip lines is decomposed into a cascade network of multiple microstrip lines and complex circuits. Secondly, the TL equations combined with the FDTD is employed to solve the voltage and current responses on these MSLs, and the effects of these MSLs on the connecting nodes are equivalent to Norton’s circuits according to the Norton’s theorem, which are incorporated into the complex circuits to form new circuit subsystems. Then, the NGSPICE software is applied for the conducted interference analysis of these circuit subsystems to solve the voltage responses on these complex circuits at each time step of FDTD simulation. Finally, the port voltages of these complex circuits are fed back to the MSLs as boundary conditions, which can obtain the effects of complex circuits to these MSLs based on the Substitution theorem. By numerical simulation of three microstrip lines terminated with one complex circuit excited by lumped voltage source, the correctness of this proposed method has been verified by comparing with that of commercial simulation software CST.