Electromagnetic Modeling of RIS-Antenna Configuration Using MoM-PO Approximation

Abstract

Reconfigurable Intelligent Surfaces (RIS) are constituted using a periodic arrangement of unit cells whose full-wave electromagnetic characterization is computationally challenging due to their large electrical size. Although planewave approximation modeling with periodic Green’s function can provide a rough estimate of its scattering characteristics, the mutual interaction of the unit cell elements starts to play a non-trivial role in the high-frequency band. In addition, when a finite transmitter is placed in the closer vicinity of the RIS, the plane-wave approximation becomes no longer valid. To address such use cases, this work proposes the idea of leveraging a hybrid MoM-PO technique for fast and accurate modeling of the coupled configuration of a large finite RIS and finite transmitter. Two different examples are reported to study the proposed modeling approach. The proposed technique can be further integrated to optimize different performance parameters of RIS-assisted MIMO communication.