RFID Sensor for Breaks in Cold Chain Applications

This paper presents a low-profile RFID sensor to detect disruptions in cold-chain operations. The sensor consists of a modified meander line resonator with a UCODE G2iL RFID chip positioned at its center. It is tailored to monitor the ice's presence of ice on its surface, operating within an impedance bandwidth of 913 – 922 MHz, which is compatible with the European RFID band. The sensor's resonant frequency is sensitive to changes in permittivity, as the Material Under Test is placed atop the sensor. When ice melts into water, the overall permittivity increases, causing a reduction in the sensor's resonant frequency. If excessive water accumulates, the sensor's resonant frequency falls outside the RFID band (915 – 921 MHz), indicating a break in the cold chain. Additionally, the sensor maintains a similar E-field distribution and radiation pattern to a conventional dipole, with a maximum gain of −0.4 dBi, making it viable for practical applications.