An Integral Equation Method Using Periodic Contact-Region Modeling for Analyzing Infinitely Biperiodic Composite Structures

Based on the method of moments (MoM) using Rao–Wilton–Glisson (RWG) basis functions, a new MoM approach to analyze infinitely biperiodic structures is proposed. In this approach, the interior of each dielectric region is analyzed separately using the infinite-space Green’s function (GF), and the periodic boundary conditions are enforced on the exterior regions. A periodic contact-region modeling (PCRM) technique is introduced to model a 3-D biperiodic composite electromagnetic (EM) structure as a combination of different regions which is connected by the interfaces of successive unit cells. In addition to increasing the versatility of the surface integral equation (SIE) for periodic structures, it is also a straightforward way to decrease the long computation time for interpolating the periodic GFs. Several examples are presented to show both the versatility and efficiency of the proposed method.