Open Access. Powered by Scholars. Published by Universities.®
- Discipline
Articles 1 - 2 of 2
Full-Text Articles in Entire DC Network
A Mems Planar Fresnel Lens For Cmut Array, Shivani Nilesh Upadhyay
A Mems Planar Fresnel Lens For Cmut Array, Shivani Nilesh Upadhyay
Electronic Theses and Dissertations
This thesis presents a Microelectromechanical Systems (MEMS) planar Fresnel lens for use with a Capacitive Micromachined Ultrasonic Transducer (CMUT) array for high-resolution cardiac diagnostic imaging applications. The research exploited the excellent sound propagation and thermal properties of cross-linked silica aerogel, a nano-porous, nano-networked ultra-light-weight material, to design a planar thinfilm lens that can be easily microfabricated or integrated with a CMUT array. The designed lens, comprised of 32 various width concentric rings, was optimized to operate with a 256 element 6 MHz CMUT array. The 4 µm thick lens was designed to generate a 1.9 mm focal spot at a …
Benefits Of Quadratically Tapered Flexures For Mems Resonators And Gyroscopes, Brian Grantham
Benefits Of Quadratically Tapered Flexures For Mems Resonators And Gyroscopes, Brian Grantham
Dissertations
An investigation into the benefits of quadratically tapered flexures for MEMS resonators and gyroscopes is performed and compared to the traditional non-tapered flexure design. Quadratically tapered flexures exhibit constant strain along the outer edge of the flexure whereas non-tapered flexures have significant stress concentration near the base of the flexure. The investigation considers peak stress, thermoelastic damping (TED), nonlinearity, and sensitivity to manufacturing variations. The impact of inside corner fillets on peak stress, TED, and resonant frequency is also investigated. Five new anti-phase lever mechanism (APLM) configurations for resonators and gyroscopes are designed and analyzed using CoventorWare 10. Fabrication experiment …