A second-order domain-decomposition method for modeling material interfaces in finite-difference discretizations

Averaging the permittivity and permeability functions at the location of a material interface has become the most popular method to enforce the field continuity conditions in finite-difference discretizations of Maxwell´s equations. While this approach offers unparalleled simplicity, the global error performs poorly—worse than first-order accuracy—when the sign of the material functions changes across an interface. In this paper, a new domain-decomposition method for enforcing the field continuity conditions is introduced that offers a second-order accurate global error performance even when the permittivity and permeability functions have a sign change.