PMUT ultrasound transducers with reconfigurable bandwidth

Piezoelectric micromachined ultrasound transducers (PMUT) constitute an emerging technology that promises to revolutionize ultrasound applications, such as medical imaging, underwater communication, intrabody communication, rangefinders, etc. There are two important performance aspects for these devices: noise performance, that defines the range for ultrasound emission and reception, and bandwidth, that determines spatial resolution in imaging applications and data rate in ultrasound communications. Importantly, increasing the quality factor of a PMUT device (that is, decreasing its power loss) improves the noise performance, but comes at the cost of smaller bandwidth. The goal of this project is to use electronic feedback to tune the quality factor of PMUT devices in real time. This way, the tradeoff between noise and bandwidth can be fully exploited in a single device.

[1] Manzaneque, T., Hernando-García, J., Ababneh, A., Schwarz, P., Seidel, H., Schmid, U., & Sánchez-Rojas, J. L. (2011). Quality-factor amplification in piezoelectric MEMS resonators applying an all-electrical feedback loop. Journal of Micromechanics and Microengineering, 21(2), 025007.

[2] Gijsenbergh, P., Halbach, A., Jeong, Y., Cheyns, D., Rottenberg, X., & Rochus, V. (2020, October). Polymer PMUT array for high-bandwidth underwater communications. In 2020 IEEE SENSORS (pp. 1-4). IEEE.

Assignment

• Perform a literature review on ultrasound transducers and MEMS resonators.
• Design and optimize PMUTs based on aluminum nitride, using Comsol.
• Fabricate the designed devices, using the fabrication tools already available at EKL.
• Characterize the resulting devices with impedance measurements.
• Implement the feedback circuit with discrete components on a PCB.

Requirements

You must be motivated to work in EKL cleanroom. Experience with FEM simulation packages such as Comsol is a plus.

Contact

Last modified: 2023-02-10