Bifunctional metasurface with ultra-broadband electromagnetically induced transparency and perfect transmissive polarization conversion

This paper proposes a metasurface that can simultaneously realize the dual functions of ultra-broadband electromagnetic induced transparency (EIT) and perfect transmission linear polarization conversion (LPC). The metasurface can be regarded as two identical layers separated by air, and each layer is composed of two N-type copper resonators rotated 45° counterclockwise immediately on both sides of the F4B dielectric layer. The simulation results show that the rotating N-type resonator causes the destructive interference of the electric resonance unit’s near-field coupling magnetic resonance unit, resulting in an ultra-wideband EIT effect with a maximum transmission coefficient of 0.93 and a relative bandwidth of 40.03%. It was also found that a near-perfect transmission LPC with a polarization conversion ratio of 99.97% was obtained near the 9.06 GHz frequency. The physical mechanisms of the EIT phenomenon and LPC are analyzed using the surface current distribution and magnetic field, and the frequency dependence of some structural parameters is also analyzed to illustrate the spectral properties of the depression. The metasurface was fabricated and measured to verify its bifunctional performance. This simultaneous implementation of EIT and LPC on the metasurface provides a new approach for applications in communications, multifunctional device design, and antennas.