THE USE OF SURFACE IMPEDANCE CONCEPTS IN THE FINITE-DIFFERENCE TIME-DOMAIN METHOD

Surface impedance concepts are introduced into the finite-difference time-domain (FDTD) method. Lossy conductors are replaced by surface impedance boundary conditions (SIBC) reducing the solution space and producing significant computational savings. Specifically, a surface impedance boundary condition (SIBC) is developed to replace a lossy dielectric half-space. An efficient implementation of this FDTD-SIBC based on the recursive properties of convolution with exponentials is presented. Finally, three problems are studied to illustrate the accuracy of the FDTD-SIBC formulation: a plane wave incident on a lossy dielectric half-space, a line current over a lossy dielectric half-space, and wave propagation in a parallel-plate waveguide with lossy walls.