Domain Decomposition Analysis of Open-cavity-based Array Elements -- Roadmap Toward Analyzing Large-Scale Reflectarrays and Reconfigurable Intelligent Surfaces

Paper i proceeding, 2025

This paper describes a numerical modeling framework toward analyzing large-scale finite-sized reflectarrays and reconfigurable intelligent surfaces. A domain decomposition method (DDM) is proposed, where a single reflecting unit cell can be characterized in isolation from its embedded structure. The mutual coupling between unit cells is occurring only over-the-air and is modeled through a generalized admittance matrix approach. Both the radiated and scattered fields, which are computed for a transmitting and scattering problem, respectively, are in excellent agreement with those computed by CST Microwave Studio and a plain MoM approach. Recommendations and future directions are provided as part of the herein presented roadmap, among which the hybridization with fast methods and high-frequency techniques capable of handling the large-scale exterior domain, and the use of a finite difference/element method for modeling the interior domain of complex unit cells.