Domain decomposition and upscaling technique for metascreens

Abstract

Purpose This paper aims to consider a multiscale electromagnetic wave problem for a housing with a ventilation grill. Using the standard finite element method to discretise the apertures leads to an unduly large number of unknowns. An efficient approach to simulate the multiple scales is introduced. The aim is to significantly reduce the computational costs. Design/methodology/approach A domain decomposition technique with upscaling is applied to cope with the different scales. The idea is to split the domain of computation into an exterior domain and multiple non-overlapping sub-domains. Each sub-domain represents a single aperture and uses the same finite element mesh. The identical mesh of the sub-domains is efficiently exploited by the hybrid discontinuous Galerkin method and a Schur complement which facilitates the transition from fine meshes in the sub-domains to a coarse mesh in the exterior domain. A coarse skeleton grid is used on the interface between the exterior domain and the individual sub-domains to avoid large dense blocks in the finite element discretisation matrix. Findings Applying a Schur complement to the identical discretisation of the sub-domains leads to a method that scales very well with respect to the number of apertures. Originality/value The error compared to the standard finite element method is negligible and the computational costs are significantly reduced.

Enhanced WPT structures via EC-SRR-based metasurfaces

“…Since the initial concept, several configurations using metamaterials have been presented (Ranaweera et al , 2019; Zhang et al , 2019; Bui et al , 2020; Rong et al , 2021; Lan et al , 2022), while instructive WPT realisations have, also, encompassed other emerging scientific domains (Li et al , 2018; Das et al , 2019; Gong et al , 2022; Tian et al , 2022; Wang et al , 2022). To this aim, the split-ring resonators (SRRs) are deemed the most commonly used elements, which conduct field amplification by modifying the electric and magnetic field distribution, because of their negative constitutive parameters (Gámez Rodríguez et al , 2016; Corrêa et al , 2019; Leumüller et al , 2022; Majumder et al , 2022). Hence, properly tuned SRR loops lead to highly efficient devices, whose size is much smaller, compared to typical ones and can be coupled with external fields in free space, allowing fairly instructive implementations (Brizi et al , 2020; Pokharel et al , 2021; Lu et al , 2021; Wang et al , 2022; Wei et al , 2022).…”