Hybridization of Multiconductor Transmission Line Solver With Circuit Solver Ngspice to Treat Line Interconnections and Terminations

This article presents the hybridization of a multiconductor transmission line (MTL) solver, implemented using the finite-difference time-domain method, with the circuit solver ngspice to treat the terminations and interconnections of transmission lines. Transient analysis and crosstalk in MTLs have been widely studied, but the line terminations and the connections between lines are mostly restricted to lumped resistors, inductors and capacitors (RLC) components. However, realistic systems, such as power distribution or communication systems, typically involve more complex and a priori unknown connections. By integrating the MTL solver with a circuit solver, the proposed approach enables the inclusion of any component for which a circuit model can be written or already exists, i.e., dispersive elements, such as ferrites, and electronic components, such as diodes, amplifiers, or transistors. This capability makes it possible to simulate the MTL networks with complex, including nonlinear, terminations and interconnections modeled by circuits. The proposed method is validated through comparison with experimental laboratory measurements.