A Pulsed Wave Doppler Ultrasound Blood Flowmeter by PMUTs

This letter describes a blood flowmeter by the pulsed wave Doppler (PWD) ultrasound detection procedure utilizing piezoelectric micromachined ultrasonic transducers (pMUTs) with the aluminum nitride (AlN) film as the piezoelectric material. The transceiver electronics for the PWD scheme is constructed for system control and signal processing, and a blood-mimicking fluid (BMF) is synthesized for flow velocity tests. Both the average Doppler frequency and Doppler power spectrum density (PSD) shift with respect to the flow velocity have been characterized and validated and the flow direction can also be recognized. Finally, a real-time pulsatile flow measurement is demonstrated to emulate the feasibility of monitoring blood flows in practice.