Optically transparent triple and dual band terahertz metamaterial absorber based on indium tin oxide and PET substrate

A simple optically transparent polarization and angular insensitive triple and dual band Terahertz (THz) Metamaterial Absorber (MMA) is designed and analysed in this paper. The MMA consists of three layers, dielectric layer is placed in-between the ground plane and top metallic patch. Without using stacked layers, doping and multiple resonators the absorber is designed here. The metal and substrate used here is Indium Tin Oxide (ITO) and Polyethylene Terephthalate (PET). The ITO with PET combination produces the optical transparency. The important thing in this work is the same design produces the triple and dual band operation while changing the top patch radius value. The absorber produces the triple band operation when the radius of the top circle is 65 μm and it produces the dual band when the radius of the top circle is 55 μm. It covers the frequency ranges from 0.3 THz to 1.4 THz. The designed structure is analysed by electric field, magnetic field distribution and surface current distributions. This structure is polarization and angle independent up to 90 degrees. From the parametric analysis, we found this absorber will work in both triple and dual band operation. So, this bifunctional working absorber will find more applications in optically transparent devices, sensing and imaging.