Enhancing Quality Factor of Chipless RFID Sensors by Optimising the Substrate Properties and Resonator Geometry

The quality (Q) factor of chipless RFID sensors is essential to improve their performance and reliability for various sensing applications. Previous research has relied on the reader's sensitivity, making the system more complex and costly. Therefore, this research aims to optimise the detection performance of chipless RFID sensors by improving their Q factor by optimising the properties of the substrate and geometry of the resonator. The methodology involves analysing the theoretical background of the Q factor using a slot ring resonator (SRR) and different resonator geometries (e.g., a new Pi-shaped resonator) to evaluate its impact on the Q factor. The results show that only choosing the optimum substrate thickness can further improve the Q factor. Furthermore, we compared the resonance frequency and its variation over distance to determine the detectability. These findings demonstrate that high-Q resonators, like the Pi-shaped resonator, can improve the accuracy and resolution of chipless RFID sensing applications.