Enhanced near-cloak by FSH lining

We consider regularized approximate cloaking for the Helmholtz equation. Various cloaking schemes have been recently proposed and extensively investigated. The existing cloaking schemes in literature are (optimally) within lnρ^-1 in 2D and ρ in 3D of the perfect cloaking, where ρ denotes the regularization parameter. In this work, we develop a cloaking scheme with a well-designed lossy layer right outside the cloaked region that can produce significantly enhanced near-cloaking performance. In fact, it is proved that the proposed cloaking scheme could (optimally) achieve ρ^N in RN, N≥2, within the perfect cloaking. It is also shown that the proposed lossy layer is a finite realization of a sound-hard layer. We work with general geometry and arbitrary cloaked contents of the proposed cloaking device. © 2012 Elsevier Masson SAS. Al right reserved.