Maryam Ziaei-Moayyed's Defense: This Thursday at 1pm

Roozbeh Parsa rparsa at
Mon Dec 8 10:30:55 PST 2008

University PhD Dissertation Defense

"Internal Electrostatic Transduction of RF MEMS Resonators"

Maryam Ziaei-Moayyed

Advisor: Professor Roger Howe

Department of Electrical Engineering
Stanford University

Date: Thursday, December 11th, 2008
Time: 1:00 pm 
Location: Packard Building, Room 101


Radio Frequency (RF) Microelectromechanical Systems (MEMS) resonators offer advantages in terms of power, bandwidth, quality factor, and compatibility with CMOS technology.  These resonators have many applications in wireless communications such as frequency references, filters and mixers. One of the major challenges of RF MEMS resonators is the high motional impedance.  This work describes design, fabrication, and testing of internal electrostatic transduction of MEMS resonators.  By replacing the air gap in resonators with high-k dielectrics, higher transduction efficiencies resulting in lower motional impedance and higher quality factor are achievable.  Internal electrostatic transduction allows for efficient coupling to a specific resonance mode, while achieving high quality factors. The devices were fabricated in a novel and manufacturable double-nanogap process tailored toward high frequency resonators.  Internal electrostatic transduction of a bulk-mode GHz ring resonator on a quartz substrate is demonstrated. By integrating the transducing electrode within the same vibrating structures, a Lamé-mode resonator with inherent differential drive, sense transduction and high quality factor is demonstrated. This work demonstrates the valuable potential of internal electrostatic transduction in extending MEMS resonators toward higher frequencies.  

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