Chipless RFID Sensory Array for IoT Dielectric Sensing and Material Characterisation

Accurate dielectric constant measurements are crucial in Internet of Things (IoT) sensing applications to characterise materials and their properties. This paper introduces an innovative capacitor-based chipless radio frequency identification (RFID) sensory array tailored specifically for precise measurements of dielectric constants in IoT contexts. The array incorporates Pi-shaped resonators and cylindrical capacitors, addressing challenges such as low accuracy, limited εr measuring range, and the reliance on bulky vector network analysers (VNA) as readers. Theoretical modelling, design considerations, sensor calibration, and validation processes are detailed, highlighting the array’s precision and adaptability. Real-world IoT applications are demonstrated, showcasing the array’s potential with a low-cost portable multiple-input multiple-output (MIMO) reader, Walabot. This cost-effective solution overcomes conventional limitations, offering a versatile approach to dielectric constant measurements and opening up new possibilities for diverse IoT sensing applications. The integration of this sensory array with IoT technologies demonstrates the feasibility of smarter material characterisation.