الفهرس | Only 14 pages are availabe for public view |
Abstract At present, all the systems are tending to miniaturization. Thanks to the great tech- nological advance of the silicon industry, it enabled the development of not only the electronic industry, but also the Micro-Electro-Mechanical Systems known as MEMS. MEMS gyroscopes have a great advantage concerning size, power, cost and reliability compared to other conventional mechanical and optical gyroscopes. Unfortunately, they face a great challenge in achieving high performance for strategic applications such as military and aerospace. The performance limitation is mainly due the noise level of MEMS gyroscopes that limits the sensitivity. Moreover, several nonidealities are caused by fabrication imperfections and mismatch. Several efforts were exerted to achieve higher sensitivity but most of them hit the design boundary of bandwidth-sensitivity relation. Moreover, some MEMS structures are not fully modeled. In this thesis, We summarize different beam theories for complete modeling of the four effective vibrational eigen modes of Fish-Hook shaped spring. The author implemented a new optimization algorithm for the design of Fish-Hook shaped spring. We Developed a design tool using MATLAB for the design and optimization of tuning fork gyroscope structure using Fish-Hook shaped spring. On the system and structural level, The author introduces a novel mode of operation for MEMS gyroscopes called ”Staggered Mode” that optimizes the bandwidth-sensitivity relation. We added a modification on a decoupled gyroscope structure to adopt this mode based on the previously modeled Fish-Hook MEMS spring. For Fish-Hook Model verification, we designed and implemented a tuning fork MEMS gyroscope. It was fabricated using SOIMUPS process provided by MEMSCAP occupy- ing 4 × 4mm2. We tested the structure using Wayne Kerr 6500B precision impedance analyzer and vacuum chamber in Ain Shams University integrated circuits lab. The au- thor compared the values calculated from the derived model to the finite element model simulated results using ANSYS and the testing results. The derived model showed close matching to the FEM within 1% to 3% while 5% to 10% to the testing results due to die stresses and process nonidealities. For the Staggered mode gyroscope, we designed and implemented the modified structure that was later fabricated using SOIMUPS process occupying 2.7 × 4.4mm2. The testing showed that the tuning has the capability not only to achieve a maximally flat band with enhancement more than 40%, but even can tolerate in band ripples for wider bandwidth while trading off the sensitivity. |