Flexible Graphene-Silver Nanowires Polydimethylsiloxane (PDMS) Directional Coupler

Abstract

In this research paper, graphene-silver nanowires are demonstrated as the transmission line of directional coupler fabricated on an elastomeric substrate Polydimethylsiloxane, PDMS at 2.4 GHz for wireless wearable application.In the experimental process, highly conductive of 0.6 mg/ml silver nanowires (AgNWs) is embedded in the graphene dispersion and spin coated onto flexible PDMS elastomer. The proposed directional coupler provides excellent return loss lower than −10 dB, good mutual coupling of −3 ± 1 dB and comparable phase difference between output ports between S21 and S31 with value of 90° ± 1°. Comparison of return loss and phase difference between output port performances was performed in three different angles of bending, 0,° 90° and 180°. The simulation and measurement outcomes show promising results, indicate that graphene-silver nanowires on PDMS elastomer as a good material for flexible devices and able to withstand mechanical strains without degrading the performance of the directional coupler. The compact sizes and unique properties of the coupler can be realized for wireless wearable electronics applications.