Low Voltage Driven Wearable Ultrasound Phased Array Imaging of Carotid Artery with Highly-Sensitive Curved PMUT Array

Wearable ultrasound carotid artery monitoring (WUCAM), as a convenient and non-invasive method, has become an emerging option for long-term assessment of human cardiovascular health. Particularly, piezoelectric micromachined ultrasound transducer (PMUT) provides an exciting alternative to bucky transducers in WUCAM owing to its miniaturized thickness and low impedance. However, the common planar PMUTs toward WUCAM need high driving voltage (>20V) due to its relatively low acoustic output. In contrast, curved PMUT has exhibited more excellent sensitivity than planar one, especially suitable for low-voltage phased imaging. This work presents an AlN-based curved phased PMUT array with a center frequency of ~5 MHz and a -6dB bandwidth of 50%. Clear imaging was achieved under 20Vpp excitation by 64-channel (210 m-pitch) phased array imaging mode. This low driven-voltage will facilitate the development of more compact, lightweight, and user-friendly wearable carotid artery imaging systems.