Characterization of Dielectric Properties of Graphene and Graphite Using the Resonant Cavity in 5G Test Band

Abstract

This paper presents a study about the dielectric constant ε r, dielectric loss tangent tan g(δ ) and effective electrical conductivity σ e of graphene, graphite and graphene-bakelite combination using the resonant cavity method. For this purpose, cylindrical samples with diameter of 30 mm and thickness of 4.5 mm were analyzed taking into account the central frequency f0 = 3.5 GHz, according to 5G technology standards. The constants ε r and tan g(δ ) were obtained from the resonance frequency fa of measured scattering parameters (S-parameters), when the cavity was loaded with the samples. An empirical equation was developed to model the relation between fa and ε r. With this empirical equation it was found ε r = 9.3203 and tan g(δ ) = 0.7000 for graphene and ε r = 17.1508 and tan g(δ ) = 0.2700 for graphite. The addition of bakelite in combination with graphene allowed controlling the dielectric properties of these composites. The results, obtained in this macroscale characterization, are interesting for Telecommunications Engineering, especially in the development of radiation-absorbent material, which is suitable for mitigation of interference between different wireless communication systems.