Design and Integration of a Flexible RFID UHF Antenna with a 3D Printed Fluid Channel for Liquids Sensing Applications

This article presents an innovative UHF RFID tag sensor featuring a flexible ring resonator dipole integrated with a fluidic channel. Leveraging the unique characteristics of the resonator dipole, the sensor demonstrates high sensitivity in detecting the dielectric properties of various liquids. The RFID integration facilitates wireless communication and remote monitoring, enabling real-time, continuous measurement of sensor data. The sensor's flexible design allows for easy attachment on the PLA fluid channel, enhancing its practical utility. Experimental results show a strong correlation with reference measurements obtained using traditional laboratory methods using VNA. The sensor achieves effective impedance matching up to 1 GHz, even without the presence of a liquid in the channel. Moreover, confining liquids with high dielectric constants within the channel broadens the operational range across the UHF RFID band, spanning 865 MHz to 928 MHz, and the wireless RFID tag sensor is well suited for applications requiring real-time analysis and continuous monitoring. The proposed flexible ring resonator dipole UHF RFID tag sensor, coupled with fluidic channel-based tuning, offers significant potential for applications such as chemical analysis of liquids. Its unique blend of flexibility, wireless data communication, and accurate dielectric characterization opens new avenues for noninvasive and remote sensing in liquid-based system.