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.