Surface acoustic wave devices with graphene interdigitated transducers

This paper reports the development of high performance surface acoustic wave (SAW) devices by using graphene as a virtually massless interdigital transducer (IDT) to mitigate mass-loading effects. Different layers of graphene electrodes were made and their influences on the SAW device performance were experimentally and theoretically evaluated. Results showed that 4-layer graphene with a value of sheet resistance less than 77.6 Ω/sq. and graphene IDTs of at least 80 pairs are needed to obtain the optimum performance of graphene IDT SAW devices. Furthermore, the optimal ratio of aperture/wavelength for the graphene IDT electrode was found to be 5. Graphene based SAW devices, with a resonance frequency of 154 MHz, transmission signal amplitude of 30 dB and K2 of 3.78%, were fabricated and successfully demonstrated for applications in breathing monitoring.