Research On Efficient Field-circuit Co-simulation Technology Based On Time-domain Discontinuous Galerkin Method

With the miniaturization and increasingly dense integration of microwave circuit,systems,it is of paramount importance that efficient as well as accurate simulation tools be developed to predict the resulting electromagnetic effects.At present,full-wave solvers have attracted more and more attention in the design of microwave circuit to ensure accurate prediction of the electromagnetic response of integrated components,packaging components and systems.Therefore,based on Maxwell curl equation,this paper proposes a full-wave solver for analyzing the co-simulation of electromagnetic field and circuit system,which can analyze the characteristics of field-circuit coupling systems containing periodic structure,non-periodic structure,active devices and passive devices.At the same time,we also propose a high precision time integration scheme and two solutions to improve the efficiency.The discontinuous Galerkin time domain method(DGTD)has the advantage of high accuracy and can achieve broadband responses only through a single transient simulation.Compared with the traditional time domain finite element method,DGTD method can transform the original global mass and stiffness matrices into a series of element matrices,which can realize a highly parallelized algorithm to improve efficiency.Moreover,DGTD method is easy to handle non-conformal surfaces,which is benefit to realize the hybrid of tetrahedral and hexahedral elements.Therefore,the DGTD method with arbitrary higher-order time stepping scheme is used in this paper.Different from traditional time-stepping schemes like central difference,forward difference and backward difference,ADER technique has an arbitrary high order of accuracy.Moreover,the computational cost of ADER at each time step linearly grows when the order is greater than four,which has advantages over the Runge-Kutta scheme.In addition,the equivalent circuit model and real physical model are used to analyze the diodes in circuit systems.The bat optimization algorithm is used to extract the parameters of physical model from the experiment data.In the field-circuit coupling analysis,the electromagnetic field part is linear,and the loaded circuit element part may be nonlinear.Newton's method is used to solve this nonlinear system,which is time-consuming.Moreover,the stability of the system is limited by the global time step interval.To handle these problems,two effective solutions are proposed.One is the local time stepping technique,allowing nonlinear and linear elements to update themselves with individual and optimal time intervals in accordance with the local stability condition.The other is the use of space mapping algorithm to transform the analysis of fine models to the optimizations and updates of coarse models,which can greatly improve the efficiency.