The efficient implementation of the surface impedance boundary condition in general curvilinear coordinates

This paper discusses the efficient incorporation of skin-effect losses into the nonorthogonal finite-difference time-domain technique. A survey of previous work is presented and it is shown that the exponential approximations used by previous methods may lead to considerable error when good conductors are modeled using a fine time discretization. Subsequently, an improved exponential approximation is given and applied to various curved conducting waveguide surfaces using the nonorthogonal finite-difference time-domain technique.