Wireless passive IDT strain microsensor

This paper presents the experimental results of wireless passive IDT strain microsensors, which consist of inter-digital transducers (IDTs) on piezoelectric wafers to transmit and receive surface acoustic waves. By connecting the IDTs to a small microwave antenna, the IDT microsensors are wirelessly readable by a microwave reading system. The sensors are calibrated on a static cantilever beam and used to measure the dynamic strain of a vibrating beam wirelessly. The calibrated sensitivity compares reasonably with the theoretical estimation. The feasibility of compensating for temperature variations and reading multiple sensors simultaneously and the ability to combine the sensor and the wireless recognition systems are discussed.