Piezoelectric Transducers: Strain Sensing and Energy Harvesting (and Frequency Tuning)
| Category | Online Presentations |
|---|---|
| Abstract | Acoustic pressure or mechanical force sensing via piezoelectric coupling is closely related to the harvesting of electrical energy from acoustical and mechanical energy sources. In this talk, mesoscale and microscale piezoelectric transducers for acoustic and vibrational sensing and energy harvesting will be discussed. For example, a micromachined piezoelectric microphone has been developed for aeroacoustic applications with a demonstrated sensitivity of 0.75 µV/Pa, a dynamic range greater than six orders of magnitude (47.8 –169 dB, ref . 20 µ Pa), and a resonant frequency of 50.8 kHz. In addition, acoustic energy harvesting has been demonstrated using a mesoscale (~ 2 cm) Helmholtz resonator machined in aluminum, delivering 25 mW to a resistive load at a sound pressure level (SPL) of 152 dB (ref. 20 µPa. This acoustic energy may be used to locally power a wireless active liner for suppression of engine noise in turbofan engines, where acoustic levels typically reach up to 150 dB. For space-constrained applications, a micromachined acoustic energy harvester was also recently developed. It employed a silicon-micromachined, circular, piezoelectric composite diaphragm. Experimental results indicated a maximum output power density of 0.34 µW/cm2 at 149 dB (ref. 20 µPa) and a potential output power density of 250 µW/cm2 with an improved fabrication process. Similar examples will be given for cantilever-based vibrational energy harvesters. Finally, some system considerations will be discussed for energy harvesting- powered systems. As the volume of the energy harvester is reduced, as expected, the harvestable power decreases given a specific power density for the available ambient conditions and material parameters. For system designs, the power balance between average power dissipation and average power harvesting determines the maximum duty cycle possible under specific energy harvesting conditions. |
| Bio | 
Toshikazu (Toshi) Nishida is currently an associate professor in
the Department of Electrical and Computer Engineering (ECE) and an
Affiliate Associate Professor in the Department of Mechanical and
Aerospace Engineering (MAE) at the University of Florida,
Gainesville, Florida. He is a founding member of the
Interdisciplinary Microsystems Group at the University of Florida.
His research interests include solid-state physical sensors and
actuators, transducer noise, strained semiconductor devices, and
reliability physics of semiconductor devices. He and his students
are currently investigating strain effects in piezoresistive
microelectromechanical systems (MEMS) transducers and advanced CMOS
devices, noise mechanisms in piezoresistive MEMS transducers, MEMS
piezoelectric transducers for vibrational energy reclamation, MEMS
capacitive microphones, and biomedical applications of MEMS.
He received his Ph.D. (1988) and M.S. degrees in Electrical and Computer engineering and B.S. degree in Engineering physics at the University of Illinois at Urbana-Champaign. With colleagues and students, he has received three best paper awards. He also received the 2003 College of Engineering Teacher of the Year award. He holds four U.S. patents. |
| Cite this work | Researchers should cite this work as follows: |
| Time | 11:00 AM, March 19, 2007 |
| Location | Birck Nanotechnology Center, Room 2001 |
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