Microwave applications of graphene for tunable devices

In this contribution, we simulate and design a electronically tunable microstrip attenuator based on graphene. To this aim, graphene is modeled as an ideal surface resistor at microwave frequency (5 GHz), changing with an external electric bias. The presented device includes a patch of graphene, whose characteristics can range from fairly good conductor to highly lossy material, depending on the applied voltage. By applying the proper voltage through two high-impedance bias lines, the achieved change in the surface resistivity of graphene induces appreciable change of the insertion loss of the microstrip attenuator.