Ultrasonic Wireless Power Transfer using Frequency Steerable Acoustic Transducers for Autonomous Guided Waves-based Inspection Systems

This research work presents an Ultrasonic Wireless Power Transfer (UWPT) system based on a piezoelectric transducer called Frequency-Steerable Acoustic Transducer (FSAT). FSAT’s directional properties are exploited to energize inaccessible sensor nodes and transmit the collected data in Structural Health Monitoring applications. To achieve this goal, the full monitoring system architecture is proposed, mostly focusing on the power conversion process. Experimental tests conducted on a 1 mm thick aluminum plate with two FSATs bonded at a distance of 50 cm highlighted a maximum received power of 164 μW with a 83 kHz, 23 V peak-to-peak sinusoidal voltage in transmission. This proves the possibility to power a low-end Microcontroller unit (MCU) and micropower management circuits. Moreover, open circuit voltages of 65 mV peak-to-peak were received by transmitting 3.3 V amplitude square waves at the same frequency, laying the groundwork for a guided waves-based digital data communication to outsource results of structural and environmental inspections.