Pulsed Wave Doppler Ultrasound Using 3.7 MHz Pmuts Toward Wearable Blood Flow Measurements

A 3.7 MHz piezoelectric micromachined ultrasonic transducer (pMUT) system based on the piezoelectric aluminum nitride (AlN) thin films has been developed to construct pulsed wave Doppler (PWD) ultrasound for wearable blood flow measurements. In the blood emulation experiments, Nylon powder, surfactant, glycerinum and deionized (DI) water combined blood-mimicking fluid has been prepared and the PWD transceiver circuits are built for the signal processing. The Doppler effect has shown that both the average Doppler frequency and Doppler power spectrum density (PSD) shift linearly with respect to the blood flow rate. As such, this system could be further implemented as wearable ergonomics devices for real-time blood flow measurements.