Development and Characterization of Flexible, Graphene-Based Patch Antennas for Wearable Electronics

Microstrip patch antennas are widely used in GHz range wireless communication due to their simplicity, compact size and planar structure. However, conventional materials involve rigid substrates and costly or hazardous materials. This study explores the development of flexible patch antennas using graphene-based conductive pastes. Initially a novel ink using graphite nanoparticle powder, ethyl cellulose, ethanol, and terpineol was formulated and optimized for screen printing on rigid FR-4 and flexible PDMS substrates. Simulations were carried out using CST Studio Suite for patch antennas for this paste at 2.4 GHz frequency for both FR-4 and PDMS which predicted a return loss of -12 dB and -6 dB respectively. Four-point probe measurements were carried out, and materials were optimized for the paste to obtain minimal sheet resistance (~410 Ohm/sq) prior to antenna construction. Experimental fabrication was then carried out on flexible PDMS substrates using optimized graphene-based conductive paste which yielded a measured return loss of −11.48 dB at 2.8 GHz corresponding to the dominant resonance, demonstrating acceptable antenna characteristics, confirming its suitability for wireless communication. The results confirm the feasibility of using graphene-based inks to develop cost-effective and environmentally sustainable flexible antennas via material optimization.