Research on microwave properties of CVD graphene by using multiple-layer CPW resonator

In this paper, the microwave properties, including the phase shift and the loss characteristics of the chemical vapor deposition (CVD) graphene, are investigated. The multiple-layer CPW resonator is used as measurement fixture. The effective permittivity is deduced by partial capacity techniques (PCT), the cascade matrix is analyzed by microwave network theory, and the resonance is measured by vector network analyzer (VNA). The first and second orders of the resonance mode in GHz range have been measured and studied. The experimental results based on four graphene samples show that, the resonant frequencies are shifting downward by ~15MHz and the quality factors are remarkably decreased by loading the graphene into the resonator, which indicates the large microwave loss of the CVD graphene.