Terahertz Graphene Based Metamaterial Transmitarray

This paper introduces a graphene metamaterial (GMM) transmitarray designed for terahertz applications. The unit-cell element is a multilayered metamaterial structure of a graphene split ring resonator with two variable gaps. The metamaterial properties of the unit-cell element are investigated from 0.74 to 0.94 THz for different conductivities of the graphene material. A parametric study of the transmission properties of the metamaterial unit-cell element is investigated. The radiation characteristics of 169 unit-cell elements of the three layers GMM transmitarrays are analyzed for different applied DC voltages. The gain and side-lobe level of the proposed transmitarray are improved by using an averaging process on the transmission phase used for array construction. The transmitarray introduces a high gain of about 18.5 dB at frequencies 0.83, 0.85 and 0.88 THz for chemical potentials mu(c) = 0.4, 0.5 and 0.8 eV, respectively. A full wave simulation is used to design and analyze the radiation characteristics of the graphene based metamaterial transmitarray.