An enhanced flexible time-stepping scheme for the hybrid time-domain finite element method

This paper presents a flexible time-stepping scheme for the time-domain finite element method (TDFEM) based hybrid field-circuit solver that allows subsystems of different sampling rates to be coupled in time. Because of this flexibility, the proposed time-stepping scheme could significantly improve the computational efficiency of the existing TDFEM-based hybrid field-circuit solver especially when the computational cost associated with the slow subsystems is much larger than that associated with the fast subsystems. Moreover, the efficiency of the hybrid field-circuit simulation with the proposed scheme could be further enhanced when the tree-cotree splitting (TCS) technique is applied to the TDFEM part to reduce the iteration count per time step for a preconditioned iterative solution when the time-step size for the FEM subsystem becomes relatively large.