A Conformal ADI-FDTD Formulation for the Modeling of 3-D Curved Lossy Metal Surfaces

This paper presents a conformal first-order surface-impedance boundary condition (SIBC) for the unconditionally stable alternating-direction implicit (ADI) finite-difference time-domain (FDTD) method. The model can be used to consider conductor loss of arbitrarily-shaped lossy conductors. The quality factor Q of spherical and cylindrical cavity resonators is used to investigate the accuracy of the technique. The technique is validated by comparison with analytic results and numerical data calculated using CST microwave studio (MWS). The convergence rate of the results is of second order, i.e., the error reduces to one quarter as the mesh resolution is doubled.