Design of a Polarization-Independent Dual-Band Electromagnetically Induced Transparency-Like Metamaterial

In this study, classical analogs of single and dual-band electromagnetically induced transparency are demonstrated with a four-fold symmetric metamaterial consisting of a Minkowski fractal ring resonator surrounded by a square ring resonator. The proposed metamaterials show high transmission ratios at the polarization independent resonances, as confirmed by the applied two different numerical methods. The proposed first and second metamaterials show electromagnetically induced transparency-like peaks at 8.87 GHz and 9.30 GHz with 93.2% and 93.1% transmission ratios, respectively. The two metamaterials are deliberately arranged in a 2x2 supercell array to yield a polarization independent dual-band electromagnetically induced transparency-like metamaterial. As a result, two transmission peaks emerge at 8.77 GHz and 9.22 GHz with 81.3% and 90.7% transmission ratios, respectively. Delay-bandwidth products, which are regarded as a measure of slow-light ability, are found to be 0.34 and 0.61 at the resonances of the dual-band metamaterial. The peak frequencies and transmission ratios maintain not only for different polarization angles but also for oblique angles of incidence. These features of the proposed metamaterials are promising for single and multi-band filtering applications, phase-shifters, as well as for slow light and sensing devices.