Material region division and antenna application of monolayer and multilayer graphene

In this paper we classify two material regions of graphene films according to the sheet resistance at microwave frequency, namely quasi-dielectric region and quasi-metal region. The maximum absorption point is employed to determine the material region division. Multilayer graphene can achieve very low sheet resistance in the quasi-metal region, which is a potential candidate for the transparent conductive film. A microstrip-fed graphene on quartz is utilized to verify the material region requirement for antenna application. Finally, a microwave graphene patch antenna using 20-layer high-quality graphene film is predicted to achieve realized peak gain of 5dB and radiation efficiency of 56%.