Wireless passive RFID sensor for pipeline integrity monitoring

This work presents a chipless RFID-based sensor for pipeline integrity monitoring in real-time fashion. The sensor monitors the coating lift-off from the pipeline, which is the initial step in external corrosion of a metal pipe. The sensor has a readout coil and an LC resonator on the passive tag with an interdigitated capacitor. The resonant frequency of the sensor demonstrates a strong relation to the gap between the coating and the metal pipe. The tag is built on a flexible substrate for wrapping around the pipe and to represent the pipe coating. The sensor is conformal, battery-free, and low cost which makes it suitable for pipeline monitoring in harsh environments. The resonator was tuned to 105 MHz with a Q factor of ∼115. The sensor demonstrates the maximum resonant frequency change of 11.7%, when 2 Standard Cubic Centimeter per Minute (SCCM) of air lifts the coating; and 7.46% when 4 mL of water ingress happens in between the coating and the pipe. This sensor has advantages of inexpensiveness, simplicity, and long lifetime with potential capability of prediction prior to failure in pipeline systems.