Beam and Cantilever Supported PMUTs for Enhanced Transmit Sensitivity and Linearity

Beam and Cantilever Supported PMUTs for Enhanced Transmit Sensitivity and Linearity

IEEE Sensors Journal

10.1109/JSEN.2025.3602973

https://doi.org/10.1109/jsen.2025.3602973

Shyam Trivedi, Duan Jian Goh, Prakasha Chigahalli Ramegowda, Jihang Liu, Yong Shun Teo, Hong Yan, Ravi Shankar, Naadaa Ghulaam Zakiyyan, Amal Das, Carla Lazzari, Alberto Leotti, Yul Koh

Sensitivity , Linearity , Aluminum nitride , III-V semiconductor materials , Sensors , Acoustics , Vibrations , Structural beams , Shape , Electrodes

01 October 2025

Trivedi, S., Jian Goh, D., Chigahalli Ramegowda, P., Liu, J., Shun Teo, Y., Yan, H., Shankar, R., Ghulaam Zakiyyan, N., Das, A., Lazzari, C., Leotti, A., & Koh, Y. (2025). Beam and Cantilever Supported PMUTs for Enhanced Transmit Sensitivity and Linearity. IEEE Sensors Journal, 25(19), 35930–35942. https://doi.org/10.1109/jsen.2025.3602973

This article introduces curved-beam (CB) and curved-cantilever (CC) piezoelectric micromachined ultrasonic transducers (PMUTs) using 30% scandium-doped aluminum nitride (ScAlN), comparing their performance with conventional (C-PMUT) in the 45–75-kHz range. The CC-PMUT and CB-PMUT designs incorporate 2 μ m edge slits to achieve piston-mode vibration, significantly enhancing the effective vibration area to 65% and 60%, respectively, compared to 33% for C-PMUT. This structural design improves linearity, with CC-PMUT demonstrating minimal frequency sensitivity to dc bias (±40 V) at 2.5 Hz/V, and CB-PMUT (7.5 Hz/V) both outperforming C-PMUT (100 Hz/V). Under increasing ac voltage excitation, CC-PMUT exhibits exceptional linearity with minimal resonance variation, while C-PMUTs and CB-PMUTs show nonlinear behavior with increasing frequency and stiffening effects. C-PMUT displays the highest nonlinearity, with a Duffing coefficient 2.5 times larger than CB-PMUT. The CB-PMUT exhibits the highest displacement sensitivity (1025 nm/V) compared to C-PMUT (825 nm/V) and CC-PMUT (610 nm/V). Despite its fourfold smaller area, the CB-PMUT generates comparable absolute pressure to the C-PMUT. Its exceptional normalized transmission pressure sensitivity of 77 dB SPL/V/mm2 surpasses both C-PMUT (65 dB) and CC-PMUT (67 dB), making it the highest reported among lead zirconate titanate (PZT) and ScAlN counterparts. C-PMUT demonstrates the highest receive sensitivity at 8.7 mV/Pa, followed by CB-PMUT at 4.2 mV/Pa and CC-PMUT at 3.3 mV/Pa. In pitch-catch experiments, CB-PMUT and C-PMUT detect signals up to 3.8 and 4 m, respectively, while CC-PMUT reaches 2.7 m ( 10 Vpp , 12-dB SNR threshold), demonstrating their potential for ultrasonic range-finding.

Publisher Copyright

This research / project is supported by the This research is supported by A*STAR under its Industry Alignment Fund – Industry Collaboration Projects (IAF-ICP), with Grant No. I2301E0027, Project Title: Piezo Specialty Lab-in-Fab 2.0 (LiF 2.0) - NA
Grant Reference no. : I2301E0027

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