A DC stable, well-conditioned and low-frequency regularized time-domain PMCHWT equation

Abstract

This paper introduces a low-frequency regularized time-domain PMCHWT equation, which is obtained by leveraging a multiplicative preconditioning and the quasi-Helmholtz projectors. The new formulation is free from all numerical issues of the standard time-domain PMCHWT equation at low frequencies, including dense grid breakdown, large-time step breakdown, DC instabilities, and the loss of solution accuracy. Those properties are corroborated by numerical experiments.