| The study and design of metamaterials that produces high refractive index values at different operating frequencies is important since this material parameter has applications in imaging, lithography, compact optical circuits, and miniaturized electromagnetic devices. Resolutions vary inversely with refractive index values.;Research and developments in recent years have demonstrated the design of a single frequency band, single high-refractive-index metamaterials. In this research the concept of single frequency, single refractive material has been extended with the design of dual frequency band, dual high-refractive-index metamaterials in the THz regime. Analysis show that higher refractive index at the second resonance frequency band is achievable through redesign of the structures. The designed structure consists of twenty five unit-cells with a surface area of 250 um by 250 um and a thickness of 5 um. Each cell has metallic structures embedded in a polyimide substrate. Analysis show strong electrical responses at two frequency range and the extracted constitutive parameters suggested high values of simultaneous dielectric constant, permeability and refractive indices.;The structures were also studied with changing unit cell parameters such the area, thickness and the dimensions of embedded structures, including their separation distances. Analysis shows that further modifications of the unit cell could lead to the design of a single structure having more than two high-refractive-index values at different frequencies, thus making the structure a commercially viable product for many applications. |
