Experimental Characterization of Graphene Thick Films

While the plasmonic nature of graphene at terahertz frequencies has been widely reported, investigations on the practical utility of graphene at the microwave frequencies are sparse. In this paper, an ink comprising graphene thick films of different concentrations (12.5 wt.%, 25 wt.% and 33 wt.%) is prepared for deposition, by screen printing. Detailed investigation of the surface morphology of the films using SEM and AFM reveals that the graphene films present a homogeneous dispersion of the filler with a comparatively lower surface roughness at higher concentrations, and negligible agglomerates. The films are then printed in between copper electrodes on FR-4 substrate, commonly used in RF circuits, and the measured scattering parameters analyzed.