KEYWORDS: Resonators, Microfluidics, Silicon, Chemical elements, Microelectromechanical systems, Finite element methods, Fluid dynamics, Nanoelectromechanical systems, Systems modeling, Scanning electron microscopy
Thermoelastic damping and fluid damping may collectively affect the resonant behaviors of silicon resonators. A finite element model is developed to predict the characteristics of the out-of-plane resonance, and the results are verified by experiments. The implementation of the perturbation method leads to an eigenvalue equation, from which the resonant frequency and the quality factor can be evaluated. The fluid damping problem is formulated by augmenting the governing equation with a linear damping term, whose coefficient is inversely determined from the experimental correlations. With the incorporation of the fluid damping term, the computational prediction achieves a good agreement with the experiment. The same method can also be extended to study the in-plane vibration of beam resonators.
During the past few years, many new technologies have been introduced to hearing aids for a better performance. Recently, we proposed an implantable piezoelectric hearing aid. The simulation of our hearing aid is presented with a detail study of its physical properties. However, an accurate experimental study of its performance is needed. Vibration frequency is a major factor that affects the quality of a hearing aid. Among various of existing measurement technologies,
laser measurement is always considered to be a precise approach for measuring the frequency properties for MEMS
(micro-mechanical-electrical-system) devices. In this paper, a piezoelectric transducer used as hearing aid speaker is
demonstrated and an optical measurement method for frequency measurement of our device is discussed in detail. Our measurement system is based on Mach-Zehnder interferometer system. Experimental results show that the vibration of our sample can be accurately detected using a laser beam and spectrum analyzer. The vibration frequency is calculated by measuring the intensity variance. This system aims to provide a simultaneous optical measurement with high
The design of microstructures with a high quality factor Q
value is of significant importance in many microelectromechanical system
MEMS applications. Thermoelastic damping can cause an intrinsic
energy loss that affects the Q value of high-frequency resonance in
those devices such as MEMS mirrors. We deal with the simulation and
analysis of thermoelastic damping of MEMS mirrors based on the finite
element method. Four designs of MEMS mirrors with different geometric
shapes are studied. In each model, the dynamic responses of the system
subjected to thermoelastic damping are compared to those of the
undamped modes. Then we present a systematic parametric study on
both the resonant frequency and the Q value as functions of various
representative parameters. These results are useful for early prediction
of thermoelastic energy loss, not only restricted to the MEMS mirrors but
also applicable in more general MEMS resonators and filters design.
The effects of geometry on the energy dissipation induced by thermoelastic damping in MEMS resonators are
investigated numerically using a finite element formulation. The perturbation analysis is applied to derive a linear
eigenvalue equation for the exponentially decaying rate of the mechanical oscillation. The analysis also involves a
Fourier method that reduces the dimensionality of the problem and considerably improves the computational efficiency.
The method is first validated by comparing the two-dimensional model to the existing analytical solutions for a simply
supported beam system, and then it is extended to a three-dimensional axisymmetric geometry to obtain the energy loss
as a function of the geometric parameters in a silicon ring resonator. The computational results reveal that there is a
peak value for the resonant frequency when the radial width of the ring varies. In addition, the quality factor (Q-factor)
decreases with the radial width as a monotonic function.
The design of MEMS mirror with a high quality factor is essential for many MEMS applications. Our paper deals with
the simulation and analysis of thermoelastic damping of the MEMS mirror based on the finite element method. Four
models of MEMS mirrors are designed with various geometries. For each model, the eigenfrequency of the thermoelastic
damping is investigated compared to the eigenfrequency without damping. The quality factor (Q) is discussed with a
variety of geometric parameters which may affect the Q factor. The best model among the four is presented.
More than ten percent of the population in developed countries suffers from hearing impairment. Various devices have
been invented to improve speech related hearing impaired people. Micro Electro-Mechanical System (MEMS)
implementations of acoustical sensors are important and have potential application for future hearing aid instruments.
Our paper deals with the modeling and analysis of Piezoelectric MEMS sensors for hearing aid applications. We will
present MEMS based sensor and analyze the best design for hearing aid instruments. This research will be valuable for
future miniature hearing aids.
Tunable optical filters are key components for dense wavelength-division-multiplexed (DWDM) optical networks. One of the successful mechanisms to realize the wavelength tunability is by utilizing micro-electromechanical systems (MEMS) technology. The tuning mechanism works by applying a voltage between the top mirror and the bottom electrode. Micromechanically actuated optical filters are desirable because of their wide tuning range and process compatibility with other optoelectronic devices. Modeling and simulation play important roles in the MEMS domain. In this paper, we present four different mirror models. A detailed theoretical analysis including both static and dynamic aspects was developed on the four mirror models. A record tuning range of 149 nm with a very small actuation voltage of 2.5 V is achieved for the MEMS-based tunable optical filter.
A finite element formulation is developed for solving the problem related to thermoelastic damping in MEMS beam resonators. The perturbation analysis on the governing equations of heat conduction, thermoleasticity and dynamic motion yields a linear eigenvalue equation for the exponential growth rate of nodal temperature, displacement and velocity. The numerical solutions for a simply supported beam have been obtained and compared to the analytical solutions found in literature, showing excellent agreements. The finite element formulation in this work has advantages over the existing analytical approaches in that the method can be easily extended to general three-dimensional geometries.