Implementation of surface impedance boundary conditions in upwind finite difference techniques

General dispersive surface impedance boundary conditions (SIBCs) are formulated in the time domain in conjunction with an upwind finite difference method for the solution of the Maxwell equations. The associated convolution integral is implemented using an efficient recursive technique. The technique is validated on a test problem consisting of a short Gaussian pulse impinging on a lossy dispersive half-space. The reflection coefficient obtained via this new technique is compared with the exact analytic solution and the results agree very well.