Millimeter Wave Subharmonic Mixer Implementation Using Graphene Film Coating

In this work, a subharmonic frequency mixer for millimeter wave applications has been designed.The mixing and multiplication phenomena are simultaneously achieved via a nonlinear component consisting in a microstrip line gap covered by a graphene film coating.The circuit structure is made up of various filters, which have been optimized to ensure high port-to-port isolation.The nonlinear behavior of the subharmonic frequency mixer has been experimentally evaluated within the 39-40.5 GHz RF frequency band.The frequency downconversion is achieved by mixing the RF signal with the second harmonic component of a 17.9 GHz LO signal.Conversion losses are minimized by generating a return path for IF, through the use of a quarter wavelength open-ended stub.