2026-09-21T06:37:36Z https://www.ideals.illinois.edu/oai-pmh

oai:www.ideals.illinois.edu:2142/129591 2026-02-05 col_2142_5131 col_2142_8888 com_2142_5130 com_2142_8887 com_2142_234

application/pdf en text Submission published under a 24 month embargo labeled 'U of I Access', the embargo will last until 2027-05-01 The student, Jie Yan, accepted the attached license on 2025-04-28 at 11:33. The student, Jie Yan, submitted this Thesis for approval on 2025-04-28 at 11:55. This Thesis was approved for publication on 2025-04-28 at 12:37. DSpace SAF Submission Ingestion Package generated from Vireo submission #22030 on 2025-10-19 at 19:16:23 Feedthrough-immune frequency tracking of electrostatic MEMS resonators Yan, Jie 2025-04-28 Bahl, Gaurav MEMS resonator Frequency tracking Feed-through eng This thesis introduces a novel dual-tone tracking scheme for MEMS resonators. Timing references are essential in modern technology, including communication, navigation, and daily electronics. While phase-locked loops and self-sustaining oscillators are commonly used for resonator frequency tracking, MEMS resonators introduce unique challenges, such as amplitude-frequency (A-F) effects, bias sensitivity, and feedthrough, which degrade tracking performance and stability. Inspired by the Pound-Drever-Hall (PDH) technique [1], this dual-tone tracking approach effectively mitigates these issues. By leveraging dual-tone subtraction, feedthrough is eliminated, isolating the resonator’s eigenfrequency. The scheme employs frequency conversion techniques to generate an odd-symmetric error signal centered around resonance, crossing zero precisely at the target resonance frequency. This signal is used in a feedback loop to lock a voltage-controlled oscillator (VCO) to the MEMS resonator without requiring additional reference voltage. A ∼1 MHz double-ended tuning fork (DETF) resonator was tested, demonstrating real-time frequency tracking under ambient temperature variations. The observed temperature hysteresis underscores the importance of dual-mode thermometry techniques, which utilize the resonant frequency of one mode as a temperature sensor. To address this, the proposed frequency tracking scheme is also integrated into a dual-mode temperature compensation system. Additionally, experiments conducted under low bias and drive conditions confirm the effectiveness of the feedthrough-immune approach. These findings represent a promising step toward the realization of long-term stable MEMS clocks. 2025-05 Thesis https://hdl.handle.net/2142/129591 Copyright 2025 Jie Yan Electrical & Computer Eng Electrical & Computer Engr University of Illinois Urbana-Champaign M.S. Thesis