Acoustic Wireless Power and Data Telemetry for Structural Health Monitoring

This paper proposes wireless power and data telemetry based on acoustic guided waves that travel on or through structures to enable acoustically-coupled sensor networks for structural health monitoring (SHM) of complex structures such as aircraft. Specifically, we develop adaptive Lamb-wave beamforming techniques using linear piezoelectric transducer arrays to enhance power transfer efficiency and telemetry targeting accuracy. GaN-based power amplifiers (up to 80 Vpp) and tunable low pass filter (LPF) banks (0.1-2.0 MHz) under adaptive control by an FPGA are implemented to drive such arrays. Binary frequency shift keying (BFSK) modulated on the power waveform is also proposed for data transfer in such reverberative and dispersive media. Optimal frequencies are investigated to maximize power transmission and minimize the bit error rate (BER). The proposed telemetry approach is experimentally evaluated on an SHM test bed for a drive level of 20 Vpp and achieves a power transfer of ~ 225.5 µ W at 0.5 m and a BER of 10−4 at 80 bps.