Multi-Windows Spectral Transparency and Slow Light Effect Induced by Complex Near Field Mode Coupling in Microwave Metasurface

A asymmetrical metasurface unit cell with multi-windows slow light effect is presented and studied. The metasurface unit cell is composed of one cut wire resonator and three patch form resonators of the same size. It is demonstrated by numerical modelling method the five transparency windows in transmission spectra can be induced. This effect is owing to the complex near field coupling of several bright, dark and quasi-dark modes excited in the asymmetrical metasurface unit cell. The impacts of structure parameters on transparency windows are also studied. Our results of microwave range show high group delay times $\tau\approx 27.9$ ns, delay bandwidth product $DBP=3.26$ and the quality factor $Q\approx 3\times 10^{3}$.