Uniform Two-Step Method for the FDTD Analysis of Aperture Coupling [EM Programmer´s Notebook]

A uniform two-step method is proposed for the Finite-Difference Time-Domain (FDTD) analyses of the coupling of both long and short apertures with zero or finite depth. The aperture-field singularity is first studied in the form of the field distribution and the aperture coefficients derived from the numerical integral of the related fields. The dramatic field singularity and the coefficients are mainly determined by the aperture´s width and depth, and also by the aperture´s end-edge effect. To provide an accurate modeling of the aperture without requiring huge computational-resource usage, a high-resolution standard FDTD simulation of the aperture end-edge area is used at the first step, and then the electromagnetic field singularity is used to derive the aperture coefficients from a numerical integral. At the second step, the coefficients are fully included into the contour-path laws to derive the FDTD updating equations for the fields near the aperture. Numerical results validated that the proposed method is an efficient simulation of the aperture coupling.