Wireless sensing and communication techniques are superior and preferred over tethered counterparts. Wireless system has already replaced or replacing commonly used data transmission methods for applications such as voice communication, internet, sensing, monitoring, etc. Recently, real-time infrastructure or asset monitoring for safety critical application is gaining attention, due to its ease of better visibility and predictive maintenance. A few of those applications belong to industries such as aerospace, defense, oil and gas, nuclear, etc., which require top of the line materials and an extra level of attention to safety. Every material or product used for such applications need to go through extensive testing and evaluation to mitigate any risk of failure. The next generation nondestructive evaluation system would provide sensing and characterization capabilities from raw materials to the final product for manufacturing on factory grounds as well as monitoring products’ desired operation in their respective in-service conditions. However, the current evaluation and internet-of-things (IoT)-based monitoring techniques have limited capabilities and cannot meet the sensitivity, range, versatility, and scalability requirements for these applications while being economical and maintenance-free. In this work, the current challenges associated with traditional NDE and SHM methods have been described and an alternative approach is proposed using new wireless sensing mechanisms. First, a wireless near-field high-Q sensing resonator is described, which has a high sensitivity to dielectric changes in composites and polymers. Second, a battery-free wireless communication system with enhanced range is demonstrated that overcomes high power requirements and radio frequency (RF) clutter issues. Third, passive (resistive and capacitive) sensors are integrated with the battery-free RFID platform and the sensor information is transmitted via a hybrid data frame with digital ID and analog sensor data. Fourth, the hybrid data frame is exploited further, an active piezoelectric transducer pair is used to actuate an acoustic pulse and measure time-of-flight (ToF) via the battery-free RFID tag, without using a power-hungry analog to digital conversion approach. The RFID-based wireless sensing system is versatile, scalable, and economically superior to battery-based IoT nodes and it can last for decades in field conditions without any routine maintenance that truly opens the pathway for embedded sensing in next generation NDE systems.
Read
