Development of Transmission Line Employing Graphene-Silver Nanowire/PET Structure for Application in Flexible and Wearable Devices in X-Band Wireless Communication Systems

In this study, we fabricated a coplanar waveguide using a novel graphene-silver nanowire composite structure (GNCS) on a polyethylene terephthalate (PET) substrate and then investigated its radio frequency (RF) characteristics. According to the measured results, the coplanar waveguide employing GNCS exhibited a substantially lower loss of transmission line than conventional waveguides. Furthermore, compared to the conventional graphene-based coplanar waveguide, the proposed structure allowed for lower skin depth and higher conductivity, resulting from the high electric conductivity of the silver nanowire. In addition, repetitive bending tests, which were performed to investigate the electric stability of the graphene-silver nanowire, showed that the coplanar waveguide employing GNCS offered substantially better electrical stability than the conventional graphene-based coplanar waveguide. These results indicate that the graphene-silver nanowire structure is a promising candidate for application in flexible wireless communication systems. Notably, this is also the first study to investigate the RF performance and electrical stability of a graphene-silver nanowire/PET structure.