An Accurate Conformal Weakly Conditionally Stable FDTD Scheme and Its Application on Electromagnetic Shielding Effectiveness Analysis

This paper proposes a conformal weakly conditionally stable finite-difference time-domain (WCS-FDTD) method, termed the C-WCS-FDTD method, to overcome accuracy limitations in simulating complex electromagnetic structures. The WCS-FDTD method provides significant advantages for modeling practical structures with very fine features in one or two directions, as its time step is determined solely by the coarsest spatial discretization. However, like the conventional FDTD method, it suffers from staircase error when handling complex geometries. This study presents the first implementation of conformal techniques into the WCS-FDTD method, significantly improving simulation accuracy for perfect electric conductor (PEC) structures while maintaining the original Courant-Friedrichs-Lewy (CFL) stability condition of the WCS-FDTD scheme. The study provides detailed derivations of the C-WCS-FDTD iterative equations and rigorously examines the method’s numerical stability through von Neumann analysis. Comprehensive numerical validations, including scattering characteristics of canonical shapes (sphere and cylinder) and electromagnetic shielding effectiveness (SE) analysis of practical enclosure structures, demonstrate that the C-WCS-FDTD method not only achieves superior computational accuracy but also substantially reduces simulation time for complex models compared to the traditional WCS-FDTD method. These significant improvements position the proposed method as an efficient and accurate computational tool for practical engineering applications involving intricate structures.