Co-Simulation of Coupled Electromagnetic and Nonlinear Circuit Problems using the Partial Element Equivalent Circuit Method

Abstract: Co-simulation of coupled electromagnetic (EM) structures and linear/nonlinear circuits has become a major demand in today's engineering. In many disciplines such as antenna engineering, microwave circuit design, electromagnetic compatibility (EMC), and even fairly low-frequency power electronic systems, simulation techniques capable of incorporating both EM structures and lumped circuit elements have become a necessity. EM effects such as radiation, crosstalk, and packaging, as well as circuit behaviors, should be considered in the design of new systems and products. The partial element equivalent circuit (PEEC) method is a numerical method incomputational electromagnetics that is based on an integral form of Maxwell's equations and proposes an electronic equivalent circuit for an EM structure. With the equivalent circuit for the EM structure and the ability to combine this circuit with any external circuit, PEEC is the natural choice for combining EM and circuit simulations. In this thesis, co-simulation of coupled EM and circuit problems using the PEEC method has been examined in a structured scheme. First, inclusion of linear and nonlinear circuit components in the PEEC method is studied by extension of the method and implementing those components in a developed solver. Although the simulation results show very good agreements, the implementation of the nonlinear components in the solver is shown to be a cumbersome and time-consuming task.Second, the equivalent circuits resulting from the PEEC method, along with all theexternal circuitry, have been exported to a SPICE solver. Solution time and scalability of this approach have been examined. The method, although simple in implementation, is limited to quasi-static simulation and also is shown to be impractical when dealing with real-world problems.The third phase of the work is concerned with a novel hybrid method that combines the capabilities of SPICE with a developed PEEC solver. The method establishes a link between a PEEC (EM) solver and a SPICE (circuit) solver. Having a specialized EM solver enables the developer to apply theoretical and software optimization techniques to obtain an optimal solver. On the other hand, holding a SPICE solver responsible for the circuit simulations releases the developer from implementing any nonlinear circuit component models in the solver. The approach is suitable for simulating systems of combined EM structures with N-terminal active devices and circuits. Good agreements in both the time and frequency domains, along with reasonable solution times, show the feasibility of the proposed method.