The Dynamic Microsystems Lab (DML) celebrates Yasaman Majd, a recent doctoral graduate, for successfully defending her dissertation this past summer semester and walking the stage for her PhD in Fall 2024.
Yasaman pursued her Ph.D. in Electrical Engineering at the University of Central Florida with MEMS resonators as her research focus. She has recently accepted a full-time position with Apple in Texas as a Touch Sensing Engineer.
Her dissertation entitled “Design and Optimization of Temperature-Stable MEMS Resonators for Timing Applications Based on Thin-Film Lithium Tantalate” was successfully defended on June 17th, 2024.
Dissertation Summary:
In her research, she investigates the development of a silicon-based MEMS device that achieves low-frequency variation across wide temperature ranges, high-quality factors, and low insertion loss, meeting the demands of modern communication systems. She explores the thermal behavior of S0 Lamb wave X-cut Lithium Tantalate (LT) resonators, demonstrating a zero-temperature coefficient of frequency (turnover temperature) both numerically and experimentally. These resonators are optimized for high electromechanical coupling (~5%), high turnover temperatures (>80°C), and a quality factor of ~2000 at 200 MHz. Additionally, she proposes a novel passive temperature compensation method using a heterostructure of doped silicon and rotated X-cut LT resonators to cancel both first and second-order temperature coefficients. This innovative design achieves a frequency drift of just 70 ppm across a temperature range of 20°C to 100°C at 313 MHz, significantly outperforming conventional silicon-based resonators.
DML wishes Dr. Majd all the best in her future endeavors and looks forward to her continued growth and next visit!