A Lamb wave-based liquid sensor for biomedical applications

Master thesis (2024)

Authors

W.A. Gahar Electrical Engineering, Mathematics and Computer Science

Contributors

P.J. French Bio-Electronics - EEMCS (mentor)
T. Manzaneque Garcia Electronic Instrumentation - EEMCS (graduation committee member)
E. Korkmaz Electronics - EEMCS (graduation committee member)
A.S. Sisman Bio-Electronics - EEMCS (graduation committee member)
Faculty
Electrical Engineering, Mathematics and Computer Science, Electrical Engineering, Mathematics and Computer Science
Copyright: © 2024 Widesh Gahar
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Published Date

27-03-2024

Language

English

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Faculty

Electrical Engineering, Mathematics and Computer Science

Abstract

This study presents an AlN-based Lamb wave (A0 mode) liquid sensing device designed for biomedical applications. The Lamb wave device features a 1.5 μm composite membrane consisting of a 500 nm LPCVD SiN and a 1 μm of a c-axis oriented AlN film. Additionally, an innovative 45° rotated IDT design was explored to minimize edge reflections towards the output IDT. Liquid testing experiments, involving IPA, DI water, and D-PBS, were conducted to see if the devices were able to differentiate between these liquids. Results demonstrate that the fabricated Lamb wave devices exhibit sensitivity to mass loading and can distinguish between liquids based on phase, frequency, and gain characteristics. Devices with the rotated IDT design have shown a significant increase in resonance by 15 dB, as well as enhanced sensitivity compared to those with the normal design. Furthermore, devices with the rotated design demonstrated a higher Q factor of 680, indicating superior performance over the normal design (Q factor of 450). These findings suggest that a Lamb wave device with the 45° rotated IDT design holds considerable potential for applications that demand accurate liquid characterization and detection.