Efficient Asymmetric Transmission and Unidirectional Polarization Conversion Based on Bilayer Chiral L-shape Metasurface

In this work, a novel bilayer chiral metasurface is proposed to realize efficient asymmetric transmission and unidirectional polarization conversion. The structure is optimized in order to efficiently achieve the polarization rotation of the incident linearly polarized waves. The numerical results reveal that the proposed chiral structure expresses different transmission coefficients for opposite directions while the same linearly polarized electromagnetic wave illuminates this structure, which indicates the occurrence of asymmetric transmission. The polarization conversion rate of incident waves could be higher than 99% from 8.9 to 9.7 GHz.