Keywords

Airflow sensor, Obstructive Sleep Apnea (OSA), Respiration monitoring, Time-of-Flight (ToF), TPoS-MEMS Resonator, Laminar Flow

Abstract

Sleep is essential for overall human health, influencing cognitive, emotional, and physical well-being. Respiratory-related sleep disorders, particularly obstructive sleep apnea (OSA), require early detection and effective treatment to prevent serious health complications. This dissertation explores innovative advancements in respiratory monitoring sensor development techniques, aiming to improve the diagnosis and management of sleep disorders. The sensor in this work incorporates a pair of Thin-film Piezoelectric on Substrate (TPoS) MEMS resonators operating at ~25 MHz, embedded in two oscillator circuits where frequency variations reflect changes in temperature and humidity caused by respiratory airflow. By precisely measuring airflow travel time between the resonators, the sensor calculates real-time flow rates and velocities with high sensitivity to subtle breathing pattern changes. A laminar airflow channel is carefully designed to minimize turbulence, ensuring more accurate Time-of-Flight-based airflow measurements. The system has undergone extensive experimental validation, including tests with a controlled respiration simulator that replicates human breathing patterns. Results show high precision and linearity, with the sensor accurately measuring flow rates between 0 and 10 L/min and velocities from 0 to 2 m/s, achieving an accuracy of 97.85%. Additionally, the system demonstrates excellent stability, featuring low phase noise, strong frequency response, and a high signal-to-noise ratio (SNR). The use of MEMS-based oscillators further enhances system robustness, while its low power consumption makes it ideal for continuous, real-time monitoring in both clinical and home settings.

Completion Date

2025

Semester

Spring

Committee Chair

Reza Abdolvand

Degree

Doctor of Philosophy (Ph.D.)

College

College of Engineering and Computer Science

Department

Electrical and Computer Engineering

Identifier

DP0029256

Document Type

Dissertation/Thesis

Campus Location

Orlando (Main) Campus

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