Characterization of multilayer graphene surface impedance at W-band

The characterization of multilayer graphene surface impedance at W-band frequency is addressed for the basic application at W-band. On the Cu foil substrate, small area and continuous graphene films are prepared by chemical vapor deposition method using methane as the catalyst. We have got the once and twice transferred samples, corresponding to 6, 12 layers and they are successfully transferred to the polycarbonate substrates. Based on the reflection coefficient and transmission line model, the surface impedance of the graphene at W-band is extracted. The results show that, the approach has been successfully applied to characterize graphene samples at W-band. The extracted surface impedances provide a wideband frequency independent resistance less than 0.5 KΩ level and a weak capacitive behavior which fit with the Drude conductivity model. The approach is successfully applied to characterize multilayer graphene surface impedance. The resistance decreases and the conductivity increased with the more layers graphene.