In this work, we propose a dual-band THz CMMs with combined two different sized cross-wire structures in a unit cell.
It can be found that the functional frequency region of the CMMs could be adjusted easily by changing the dielectric layer thickness and width of cross-wire. The exceptional strong polarization rotation, CD effect and negative refractive index also could be found by selecting these structure parameters appropriately.
The unit cell of dual-band THz CMMs is composed of two different sized mutually twisted metallic cross-wire separated by dielectric layer.
We can conjecture that the two resonances are corresponding to smaller size cross-wire structure, and the other two resonances are to the bigger one.
5, obviously, the first couple resonances (4.8 THz and 5.6 THz) are mainly caused by the longer bi-layer cross-wire structure, while the second couple resonances (7.9 THz and 8.2 THz) are mainly attributed to the shorter one.