Liwei Lin (Advisor)

This work presents an air-coupled piezoelectric micromachined ultrasonic transducer (pMUT) with
high transmitting acoustic pressure by using sputtered potassium sodium niobate (K,Na)NbO3
(KNN) thin film with a high piezoelectric coefficient (e31 ~ 8-10 C/m2) and low dielectric constant
(er ~ 260-300) for the first time. The fabricated KNN pMUT with a resonant frequency at 104.5 kHz
has been tested to exhibit unprecedented results: (1) high sound pressure level (SPL) of 109 dB/V
at a distance of 10 cm, which is 8 times higher than that of AlN-based pMUTs at a similar
...

This work presents an evolutionary design framework for the horn package design of piezoelectric micromachined ultrasonic transducers (PMUTs). Our framework integrates high fidelity acoustic simulations, formulations for arbitrary three-dimensional horn geometries, and a custom genetic algorithm–based shape optimization strategy to customize and improve PMUT wave directivity and amplitude in health care and wearable devices applications.

Project is currently funded by: Industry Sponsored Research

This project develops micro flying robots enabled by electromagnetic actuation and beamforming-based control, eliminating the need for onboard power sources. Distributed coil arrays generate spatially programmable magnetic fields that provide wireless power delivery and open-loop flight control through field shaping, without onboard sensing or computation. Magnetic beamforming enables stable untethered flight and maneuverability at sub-centimeter scales. The work establishes a general framework for wireless actuation of micro-scale flying robots and other untethered micro-...

As smart devices dominate larger areas of day-to-day life, their ability to communicate with human users must improve. While skin is the largest organ in the human body, relatively few efforts have gone toward developing more adaptive ways to utilize the "sense of touch" compared to visual and auditory signaling. The mechanical stimulus to generate a sense of touch by the embedded mechanoreceptors in the skin at different depths has been created in previous ways via vibratory actuators, requiring bulky and specialized offset masses and motors. In this project, we are investigating the...