Enze Huang

Surface stress-induced deflection of a microcantilever with various widths and overall microcantilever sensitivity enhancement via geometry modification

The issues of surface stress-induced deflection of a microcantilever with various widths and overall microcantilever sensitivity enhancement of microcantilever-based biosensors are investigated in this paper. A remarkably precise and simple analytical formula for calculating surface stress-induced deflection of a microcantilever with various widths is deduced. Particularly, the effect of surface stress on the location of the microcantilevers neutral axis is considered. This explicit analytical formula is validated by the finite element method simulation. An analytical equation for computing the fundamental resonant frequency of a microcantilever with various widths is also derived. This paper explores the deflections and resonant frequencies of the microcantilevers having basic and modified shapes. It is found that minimizing the effective mass near the microcantilevers free end and the clamping width at the fixed end significantly enhances the overall microcantilever sensitivity. A novel microcantilever, which is expected to have much more excellent performance and overall sensitivity than the simple rectangular-shaped microcantilever, is proposed as sensor element in biological detection.

On dynamic behavior of triangular shaped cantilevers in MEMS sensors: Effect of curvature

A study on the effect of curvature of triangular shaped cantilevers in MEMS sensors was presented. 3-D models were performed by using the SolidWorks software. And modal analysis and harmonic response analysis were carried out on different types of geometrically configured triangular shaped cantilevers using ANSYS software. The results included the variation of natural frequencies of cantilevers and maximum equivalent von mises strain on the cantilevers with respect to radius of curvature of triangular shaped cantilevers. According to the finite element analysis results, the curvature did affect dynamic behavior of triangular shaped cantilevers in MEMS sensors. Usually, the curvature is induced by the surface stress due to microprocessing or any change of temperature, etc. Therefore, in order to achieve a steady state of strain for the MEMS sensors, its better to eliminate the surface stress and make the cantilever transform from a curved cantilever to a straight cantilever.

A MEMS density sensor based on mircro-rectangular cantilever

A rectangle cantilever-type micro density sensor was researched based on MEMS (Micro Electro-mechanical System) technology. A Ti-Pt-Au coil and a Wheatstone full bridge were made on the top of the rectangle cantilever-type sensitive chip. The sensitive chip was placed in uniform strong magnetic field. The resonant frequency of the sensitive chip was changed with the change of the AC currents frequency. The resonant frequency of rectangle cantilever could be measured through the Wheatstone full bridge circuit and lock-in amplifier, and then the fluid density associated with the resonant frequency of the sensitive chip could be calculated. The static analysis, modal analysis, a first-order and third-order harmonic response analysis of the rectangle cantilever were performed with ANSYS software. The best locations of the four force-sensitive resistor of Wheatstone bridge were studied.