Eco-Sustainable RFID Antennas on Plasticized Starch Enabled by RF-Optimized Laser-Induced Graphene Transfer

Abstract

The increasing demand for sustainable RFID and sensing systems drives the transition toward biodegradable materials and low-energy fabrication. Conventional conductors and petroleum-based polymers (e.g., PET, PI) ensure high performance but lack environmental compatibility. This work introduces a near-metal-free fabrication process for conductive and biodegradable antennas based on Laser-Induced Graphene (LIG) transferred onto Plasticized Starch (PS). Since PS is unsuitable for direct laser-writing, a LIG master acts as a transfer matrix. Conductive patterns are imprinted onto the PS film through a low-temperature curing and peeling process. A parametric analysis identifies the optimal curing conditions, assessing the morphological homogeneity and the electrical stability of the transferred traces. Results demonstrate a sheet resistance as low as $4.8\ \Omega /\mathrm {sq}$ with nearly 100% geometrical integrity and excellent adhesion. As a demonstrator, a C-dipole antenna for smart packaging is fabricated and tested, exhibiting high robustness against repeated bending and reliable operation in realistic scenarios. Applied to food-filled packages, the antenna provides a read range of 45–60 cm, in the worst case scenario, which is compatible with proximity identification on smart shelves. By combining a bio-derived substrate with a carbon-based conductor, this platform eliminates the need for metal-plastic separation, significantly reducing the complexity of end-of-life recovery.