A Full-Dielectric Chiral Material Based on a Honeycomb Structure

Ismael Barba,José Represa,Gregorio J Molina-Cuberos,Ángel J García-Collado,Ana C L Cabeceira,Ana Grande

doi:10.1155/2018/4198243

Abstract

A uniaxial bianisotropic, full-dielectric structure has been designed and numerically studied. The material is based on a previously published 2D-honeycomb structure. A 3D expansion leads to an effective metamaterial showing a typical chiral electromagnetic behavior, i.e., a resonant electromagnetic activity with a small circular dichroism.

Highlights

Hexagonal structures with sixfold symmetry have been widely used in different sectors, such as aerospace or construction, thanks to their special properties [1, 2]
In 1989, Wojciechowski and Brańka proposed a “tilted” honeycomb, with sixfold symmetry but no mirror symmetry in a plane, as a way to obtain a negative Poisson’s ratio [3]
In 2004, it was predicted that materials with strong electromagnetic activity can possess a negative refractive index [7], and since several chiral metamaterial (CM) designs have been proposed and probed to produce such a negative refractive index [8, 9]

Summary

Introduction

Hexagonal structures with sixfold symmetry ( known as “honeycombs”) have been widely used in different sectors, such as aerospace or construction, thanks to their special properties (mechanical, optical, thermal, etc.) [1, 2]. Contrary to regular honeycombs, it expands in all directions when it is pulled in only one of them Structures of this kind are called “auxetic” honeycombs. From an electromagnetic point of view, chiral structures are known for their potential to show a reciprocal electromagnetic cross-coupling in their effective constitutive relations (bi-isotropy or bianisotropy) [5]. This property leads to different possible effects: first, the eigenmodes of a plane wave travelling through such materials are left- and right-handed circular polarized (LCP and RCP, respectively) waves [6]. The effective Pasteur (chirality) parameter has been extracted from the S-parameters, showing a resonant behavior similar to the one found in other chiral structures (i.e., the Condon model) [5], but with (a) low energy losses

Chiral Bi-isotropic Media

Structure under Study

Results and Discussion

Conclusions

Conflicts of Interest