Broadband conductivity of graphene from DC to THz

In this paper for the first time we have studied the broadband sheet conductance of few-layer graphene on single-crystal quartz substrate. Few-layer graphene was grown on Nickel coated Si wafers and transferred to the target substrate, which is single crystal quartz. High frequency measurements at X-band (8–12 GHz), using WR90 waveguide were performed. In addition, sheet resistance at W-band (75–100 GHz) and 1 THz range is also measured providing a comprehensive frequency sheet conductance calculation. The sheet resistance is extracted form the transmission coefficient (S 21 ). The results present small variation at different frequency bands, and are quite stable within the bands.