The graphene is a native one-atom-thick crystal consisting of a single sheet of carbon atoms. In this material discovered in 2005, the elec-tron transport is ballistic at room temperature and is described by a quantum relativistic-like Dirac equation rather than by the Schrödinger equation. Also, graphene has a Young modulus of 1.5 TPa. Due to these unique properties .graphene is considered to be a very promising material for high frequency na-noelectronic devices such as oscillators and switches. In this paper, we will show that a single graphene barrier acts as a switch with a very high on-off ratio and displays a significant differential negative resistance at frequencies be-yond 1THz. Also, we will show that graphene can be used in a very efficient RF-NEMS switch for microwave applications.