Design of a bi-functional metamaterial with broadband electromagnetically induced transparency and transmission-type polarization conversion

In this study, a metamaterial comprising an N-type strip (NS) and a double split-ring resonator (DSRR) has been investigated, which is the first to exhibit the broadband electromagnetically induced transparency (EIT) effect and dual-band transmission-type polarization conversion under microwaves. The transmittance coefficient reaches a maximum value of 0.94 at 13.10 GHz, while the bandwidth of the transparency window is 4.96 GHz. At 9.48 GHz and 14.36 GHz, almost all the transmitted co-polarization waves are converted into cross-polarization waves at the polarization conversion ratios of 95% and 94%, respectively. The surface current distributions have been used to analyze the phenomena of EIT and transmission-type polarization conversion. The group delay value (15.35 ps) is calculated to exhibit the slow light effect at the transparency peak. It is expected that the proposed metamaterial will be beneficial for manufacturing slow-light devices and for communication applications.