Mass sensor using mode localization in two weakly coupled MEMS cantilevers with different lengths: Design and experimental model validation

Abstract

This paper presents a sensor using the mode localization phenomenon to detect a mass perturbation. It is composed of two cantilevers with different lengths and connected by a coupling beam. The short cantilever is electrostatically actuated and by changing the applied DC voltage, we can reduce its stiffness and reach the veering point, which corresponds to a balanced system. This principle allows us to overcome the manufacturing defect which perturbs the initial system. An analytical model using the Euler-Bernoulli beam theory is developed for the design. The equation of the continuous system is discretized with the Galerkin method and simulations are performed. The designed device composed of polysilicon coupled microbeams is then fabricated with the MultiUser MEMS Processes and an experimental investigation is carried out. Three devices with different coupling are considered with a length ratio of 0.98. This ratio is suitable to reach the veering point by using a DC balancing voltage around the half of the pull-in voltage. The comparison between theoretical and experimental results shows a good agreement for each device.

Cantilever-Based Sensor Utilizing a Diffractive Optical Element with High Sensitivity to Relative Humidity

“…Microcantilever-based sensors have also been demonstrated as a novel mean of measuring the degradation of biopolymers used as carriers in drug delivery devices [ 17 ]. Thus, they have potential applications as biosensors, chemical sensors, portable devices, medical devices and security control [ 17 , 18 , 19 , 20 ]. Consequently, the microcantilever-based sensors can offer the opportunity of measuring various analyte species in low concentration but also investigate the fundamental interactions among these species.…”

Dynamic Behavior of T-beam Resonator With Repulsive Actuation

“…Determining the microstructure's natural frequencies as accurately as possible is crucial for characterizing their actual geometry and boundary conditions, revealing their operating range and restrictions, and enabling accurate calibration of resonator-based devices [24]. Set damping term c = 0 and forcing terms V = 0, linear eigenvalue problem is obtained: Using separation of variables W (x, t) = φ(x)q(t) and settingq(t) = −ω 2 u(t), where ω stands for non-dimensional natural frequency, the mode shape is written as φ(x) = c 1 cos(βx)+c 2 sin(βx)+c 3 cosh(βx)+c 4 sinh(βx)…”

Ultra-Precise MEMS Based Bio-Sensors

“…In the past few years, in the MEMS community, a paradigm shift is observed in the design and implementation of micromechanical resonating sensors. A new perspective is presented in using 1-d chain of a coupled resonating proof masses, more familiarly refereed as multi degree-of-freedom (m-DoF) array, coupled resonator (CR) array, weakly coupled resonators (WCR) or mode-localized sensors [20][21][22][23][24][25][26][27][28]. Figure 1 shows a representative schematic for such system.…”