A Bilayered, Broadband, Angularly Robust Chiral Metasurface for Asymmetric Transmission

Asymmetric transmission (AT) through metasurfaces yields a direction-sensitive behavior for electromagnetic (EM) wave propagation. To date, majority of the reported works operate at normal incidences alone and are, therefore, highly prone to variations under oblique incidences. In contrast, the chiral metasurface presented in this letter is robust up to 60^{\circ } incident angle while yielding a transmission magnitude above 80% for an operational-range of 8.1-9.3 GHz in a thin bilayered configuration. Furthermore, since a miniaturized unit-cell is the key to angular robustness of the metasurface, a lumped-model development methodology to determine its resonant frequency is presented. Lastly, it is shown that the reported metasurface can geometrically be scaled to the lower ends of microwave spectrum, thus increasing its utility for mainstream applications. The results have been analytically and experimentally validated and yield state-of-the-art features in comparison to previous works in microwave regime.