Finite frequency external cloaking with complementary bianisotropic media

TL;DR

This paper explores finite frequency external cloaking using complementary bianisotropic media, demonstrating enhanced or reduced scattering effects and novel cloaking configurations through numerical simulations.

Contribution

It introduces a new approach to external cloaking at finite frequencies using NRHB media, including cylindrical lenses and space cancellation techniques.

Findings

NRHB shells can enhance or reduce scattering depending on configuration.

Space cancellation with NRHB media enables external cloaking of objects.

NRHB lenses and slabs can hide dipoles via the ostrich effect.

Abstract

We investigate the twofold functionality of a cylindrical shell consisting of a negatively refracting heterogeneous bianisotropic (NRHB) medium deduced from geometric transforms. The numerical simulations indicate that the shell enhances their scattering by a perfect electric conducting (PEC) core, whereas it considerably reduces the scattering of electromagnetic waves by closely located dipoles when the shell surrounds a bianisotropic core. The former can be attributed to a homeopathic effect, whereby a small PEC object scatters like a large one as confirmed by numerics, while the latter can be attributed to space cancelation of complementary bianisotropic media underpinning anomalous resonances counteracting the field emitted by small objects (external cloaking). Space cancellation is further used to cloak a NRHB finite size object located nearby a slab of NRHB with a hole of same shape and opposite refracting index. Such a finite frequency external cloaking is also achieved with a NRHB cylindrical lens. Finally, we investigate an ostrich effect whereby the scattering of NRHB slab and cylindrical lenses with simplified parameters hide the presence of dipoles in the quasi-static limit.