A separated potential integral equation for low-frequency PMCHWT

The conventional PMCHWT method for solving multi-region dielectric problems at low frequencies gives rise to an ill-conditioned method of moments matrix when solved using the traditional RWG basis. This leads to problems in iterative convergence in a fast solver framework, namely large iteration count or inaccuracies in the solution. To alleviate the problem, quasi-Helmholtz decomposition by loop-tree or loopstar bases is often performed. However, it is a time-inefficient process to extract loops from complex real-world structures containing multiple holes and handles. To avoid this bottleneck, a separated potential integral equation formulation is proposed (SPIE-PMCHWT) in this paper for solving low frequency illconditioning of PMCHWT problems.