Efficient asymmetric transmission for wide incidence angles using bi-layered chiral metasurface

Abstract

An ultrathin bi-layered chiral metasurface manifesting asymmetric transmission for linear polarization is designed and experimentally demonstrated. By breaking certain symmetries of the chiral structure, the proposed design is enabled to convert a y-polarized wave into an x-polarized upon transmission in the forward direction with transmission coefficient 0.95 while an x-polarized wave is completely reflected. On the other hand, in the backward direction, an x-polarized wave is transformed into y-polarized with transmission coefficient magnitude of 0.95 while a y-polarized wave is reflected. More importantly, the proposed structure maintains asymmetric transmission characteristics for oblique incidence up to 60º both for transverse electric and transverse magnetic polarizations. It is shown that unlike linear polarization, the proposed metasurface shows no propagation direction-dependent characteristics for circular polarization. The ultrathin thickness (0.026λ at 10 GHz), efficiency and high angular stability qualifies the proposed metasurface to be a promising candidate for integration with numerous microwave devices.

Ultra-wideband, Wide Angle, Asymmetric Transmission based Chiral Metasurface for C and X Band Applications

“…However, its performance degrades at higher oblique incidences. The designs in 35 performance up to 60 • and 40 • in bi-layered and tri-layered configurations, respectively, however, they are limited to a narrow band operation. Furthermore, the recent publication by the authors 31 although achieves an angularly robust performance up to 60 • , however is limited to a bandwidth of 18% that has been improved with a tri-layered variant of the design which ensures a ultra-wide operational bandwidth of 64% with a wide angle performance up to 45 • .…”

“…32 , though ensures robust operation up to 30 • , however its magnitude decreases at higher incidences. 35,36 present angularly robust AT devices, however they are severely limited in terms of bandwidth. Authors in their recent work 31 have also proposed a bi-layered AT device that manifests angular performance up to 60 • , however, its bandwidth though broad, can still be improved to incorporate multi-band operations.…”

Ultrathin chiral metasurface with multiple functionalities

“…While most of the reported structures exhibit the AT property over a single frequency band, MSs which exhibit AT within more than one frequency band can also be found in literature 14,16,19,22,26,29 . However, only a handful of the presented AT exhibiting MSs have good angular stability 10,11,22,28,29 . Most of the other structures have poor angular stability and their operations are confined to a narrow range of incident wave angles.…”

“…Many bi‐layered and multilayered MSs that can exhibit this AT property are found in literature 10–29 . While most of the reported structures exhibit the AT property over a single frequency band, MSs which exhibit AT within more than one frequency band can also be found in literature 14,16,19,22,26,29 .…”

High-efficiency modulation of broadband polarization conversion with a reconfigurable chiral metasurface

“…The operation band of a metasurface can be widened effectively considering the interlayer coupling effect of the local resonant modes; 40 the laminated structure of the anisotropic open resonant ring has been employed to realize the broadband polarization conversion and asymmetric transmission. 41 The AT effect and polarization conversion of electromagnetic waves on the metasurface structures have been studied in the range of microwaves, [42][43][44][45][46][47] terahertzs [48][49][50][51] and optical band. [52][53][54][55][56] The design of these structures can be used for polarizers and have practical applications in imaging, communication and sensing.…”