Vibration transmission and support loss in MEMS sensors

Chouvion, Benjamin (2010) Vibration transmission and support loss in MEMS sensors. PhD thesis, University of Nottingham.

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Abstract

Micro-Electro-Mechanical Systems (MEMS) inertial sensors that are based on a resonating structure are used in a wide range of applications including inertial guidance and automotive safety systems. Damping has a significant and negative effect on sensor performance and there is an increasing need to accurately predict and control damping levels, particularly for high performance guidance and navigation applications. Support loss, which governs the losses from the resonator to its foundation through the supporting structure, is an important source of damping in MEMS resonators. This thesis focuses on improving the understanding of this particular damping mechanism and on developing efficient models to predict support loss at the design stage.

The coupling between resonator and support is of primary interest when evaluating the interaction and energy transmission between them. To quantify the stresses acting on the support, a model that predicts vibration transmission through common MEMS structures is first developed. A general wave propagation approach for the vibration analysis of networks consisting of slender, straight and curved beam elements, and a complete ring is presented. The analysis is based on a ray tracing method and a procedure to predict the natural frequencies and mode shapes of complex ring/beam structures is demonstrated, for both in-plane and out-of-plane vibration. Furthermore, a simplification of the analysis for cyclically symmetric structure is presented. An analytical method is then used to model the support, approximated as a semi-infinite domain, and to quantify support losses, again for both in-plane and out-of-plane vibration.



To illustrate the effectiveness of the models, several numerical examples are presented, ranging from simple beam-like structures to ring/beam structures of increasing complexity. A parametric study on the design of particular ring-based resonators, and general strategies for improving the quality factor of common MEMS sensors by reducing support losses, are also considered.

Item Type:Thesis (PhD)
Supervisors:McWilliam, S.
Popov, A.A.
Faculties/Schools:UK Campuses > Faculty of Engineering > Department of Mechanical, Materials and Manufacturing Engineering
ID Code:1293
Deposited By:Mr Benjamin Chouvion
Deposited On:21 Oct 2010 13:58
Last Modified:21 Oct 2010 13:58

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