High-Order Interface Treatment Techniques for Modeling Curved Dielectric Objects

Three modified conformal techniques combined with high-order finite-difference time-domain method (FDTD (2, 4)) are proposed to investigate the interaction of electromagnetic waves with three-dimensional (3-D) curved dielectric surfaces. These proposed conformal techniques utilize an effective average dielectric constant to modify the update equations in the FDTD (2, 4) scheme, which is derived by area, linear, and volume averages of different dielectric regions in twenty seven spatial discrete cells at most, respectively. Some numerical results are presented to show the accuracies of linear and area average techniques. Good agreements are obtained with those of the method of moments and other analytical ones, even with coarse meshes adopted for handling electrically large or complex geometries effectively. Further, using our proposed techniques, the RCS of some typical 3-D objects are predicted and studied in detail.