Date of Award
2-28-2025
Publication Type
Doctoral Thesis
Degree Name
Ph.D.
Department
Electrical and Computer Engineering
Keywords
Capacitive Resonator, Configured-Boundary, Gas Sensor, Mass Sensitivity, Microelectromechanical Systems (MEMS), Microfabrication
Supervisor
Arezoo Emadi
Rights
info:eu-repo/semantics/embargoedAccess
Creative Commons License
This work is licensed under a Creative Commons Attribution-NonCommercial-No Derivative Works 4.0 International License.
Abstract
Gas sensing technologies are essential tools in several fields such as environmental monitoring and public health, where they enable the early detection of hazardous compounds and facilitate timely interventions. In healthcare, these technologies support non-invasive, early disease diagnosis by identifying specific compound signatures, reducing the need for traditional laboratory tests and improving accessibility. However, detecting compounds at extremely low concentrations such as part per billion (ppb) or part per trillion by volume (pptv) poses technical challenges that require highly sensitive solutions. While various gas sensing technologies exist, including mass resonators, electrochemical, and acoustic sensors, each has limitations in terms of sensitivity, selectivity, or temperature dependency. Capacitive-based resonators have shown promise as candidates for detecting low concentrations of compounds due to their capability of detecting concentrations at the ppb level. However, their performance is constrained by limited plate deflection, which restricts the achievable change in capacitance and, thus, their mass sensitivity. To address this limitation, this dissertation introduces a novel configured boundary approach which is designed to enhance the performance and mass sensitivity of capacitive-based resonators by increasing plate deflection and the resulting change in capacitance. The proposed approach is applied to the design and development of configured boundary capacitive-based resonators, fabricated using a multi-user process to prove the concept. The proposed resonators are evaluated through comprehensive electrical and optical characterizations as well as mass sensitivity. Electrical characterization is performed by measuring the resonant frequency via impedance, while the optical evaluation demonstrates the impact of the configured boundary approach on the plate’s static deflection. To prove the improved performance and increased mass sensitivity, the fabricated resonators are tested in a controlled environment with varying humidity levels. Compared to conventional fully clamped devices, the proposed resonators show enhanced performance, with increased plate deflection and improved capacitance change, highlighting the effectiveness of the configured boundary approach. This work offers a practical solution to improve the performance of capacitive-based resonators without adding complexity to the fabrication process, making contribution to the field of high-sensitivity compound detection and expanding the applicability of these sensors across multiple domains.
Recommended Citation
Nazemi, Haleh, "Development of Novel Boundary-Configured Capacitive Gas Sensors Using MEMS Platform" (2025). Electronic Theses and Dissertations. 9695.
https://scholar.uwindsor.ca/etd/9695
