Developing a phased PMUT array patch for cardiac health monitoring

This work presents a novel piezoelectric micromachined ultrasound transducer (pMUT) developed using flat panel display (FPD) technology. The pMUT phased array is a key step toward creating a large-area, flexible patch for cardiac health monitoring. By developing the pMUT on large glass and polymer substrates that can be integrated with thin film transistors (TFTs), it enables the production of large-area pMUTs controlled by TFT circuits through an inexpensive process, while maintaining high uniformity and performance levels comparable to silicon-based pMUT technology. The prototype presented in this work achieves a surface transduction efficiency of 4.9 kPa/V and a focused pressure transduction efficiency of 17 kPa/V at a distance of 10 cm from the transducer. The transducer's bandwidth is 117% at a resonance frequency of 2.4 MHz. Furthermore, cardiac imaging performed using the transducer clearly displays internal features of the heart, including the left ventricle, interventricular septum, and the aortic and mitral valves, demonstrating its potential as a cardiac output monitoring device.