Sandwiched Graphene Clad Laminate: A Binder‐Free Flexible Printed Circuit Board for 5G Antenna Application

Metal substitution is always the focus of scientific research in printed circuit board (PCB) and 5G communication technology. It is proved that the high thermal conductive carbon‐based materials can be potential alternatives. However, the relatively low electrical conductivity and the difficulties in integrating carbon‐based materials to functional substrates limit their further and industrial applications. Herein, a method is developed to fabricate large‐scale, binder‐free, flexible graphene clad laminate (GCL) by hot pressing assistant under vacuum to achieve excellent electrical properties and well‐connected interface for PCB application, thus accomplishing metal substitution. GCL is a sandwich structure construct of top and bottom layers of high‐conductivity graphene assembled film as a conductive layer and a dielectric substrate layer. A 5G millimeter wave antenna array based on GCL PCB operated at 26 GHz is designed, fabricated, and characterized. The GCL antenna array has a reflection coefficient of −20.98 dB and a realized gain of 11.05 dBi, which are comparable to the metal antenna array made of the commercial copper clad laminate‐based PCB. All the measurement results show that the flexible and lightweight GCL can be used as a new generation PCB for flexible electronic devices and radio frequency devices.