1,720,975 research outputs found
Simulation and Experimental Validation of a Flexural Plate Wave Piezoelectric MEMS Transducer
No full textThe analysis and experimental validation of the frequency response of the electrical conductance of a piezoelectric micro electro-mechanical systems (MEMS) Flexural Plate Wave (FPW) transducer is investigated in this paper. FPW MEMS transducers are an attractive research field due to the considerable number of possible applications such as vibration, pressure, humidity measurements, chemical vapour and gas detection, biosensing, and lab-on-chip development. To this extent, this work proposes a theoretical analysis supported by finite element modelling (FEM) by means of COMSOL Multiphysics® and LTspice modelling of a flexural plate waves piezoelectric MEMS transducer configured as a one-port device. The transducer embeds an aluminum interdigital transducer (IDT) located close to the edge of a squared diaphragm composed of a silicon (Si) and a piezoelectric aluminum nitride (AIN) layer. The developed analysis together with the FEM and LTspice simulations have been experimentally validated by employing a fabricated MEMS transducer. The presence of multiple standing waves was correctly detected within the expected bandwidth, in good agreement with theoretical predictions. © 2024 IEEE
Servo-Assisted Position-Feedback MEMS Inclinometer with Tunable Sensitivity
No full textIn this paper a Micro Electro-Mechanical System (MEMS) inclinometer based on a double-actuator electrical servo-assisted position-feedback mechanism is presented. The mechanical position of the moveable part of the system is kept fixed thanks to a position-feedback loop that exploits a capacitive position sensor and two electrostatic force actuators. By adjusting specific loop parameters, the angle sensitivity can be finely tuned electrically. Experimental results show that the proposed system allows to tune the sensitivity up to 33.1 mV/deg, and to obtain a maximum angle resolution of 40 mdeg
Identification of MEMS Geometric Uncertainties through Homogenization
Full text linkFabrication imperfections strongly influence the functioning of Micro-Electro-Mechanical Systems (MEMS) if not taken into account during the design process. They must be indeed identified or precisely predicted to guarantee a proper compensation during the calibration phase or directly in operation. In this work, we propose an efficient approach for the identification of geometric uncertainties of MEMS, exploiting the asymptotic homogenization technique. In particular, the proposed strategy is experimentally validated on a MEMS filter, a device constituted by a complex periodic geometry, which would require high computational costs if simulated through full-order models. The complex periodic structure is replaced by an equivalent homogeneous medium, allowing a fast optimization procedure to identify imperfections by comparing a simplified analytical model with the experimental data available for the MEMS filter. The actual over-etch, obtained after the release phase, and the electrode offset of a fabricated MEMS filter are effectively identified through the proposed strategy
MEMS sub-nanonewton force sensor with tunable sensitivity and servo-assisted position-feedback
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Electronic technique and system for non-contact reading of temperature sensors based on piezoelectric MEMS resonators
No full textThis work investigates an electronic technique and system for non-contact reading of the temperature-dependent resonant frequency of piezoelectric MEMS resonators. The proposed approach exploits magnetic coupling between an interrogation unit and a sensor unit to achieve non-contact operation. A dedicated electronic circuit in the interrogation unit alternatively switches the system between the excitation and detection phases, thus implementing a time-gated technique. The MEMS resonator in the sensor unit is driven into resonance during the excitation phase, while its damped response is sensed in the detection phase. An electronic circuit down-mixes the damped response of the resonator and the frequency of the resulting signal is measured through a post-processing technique based on autocorrelation. The system has been applied to the reading of a temperature sensor based on a MEMS aluminum-nitride thin-film piezoelectric-on-silicon disk resonator vibrating in radial contour mode. The experimental characterization of the non-contact system determined the temperature coefficient of frequency of the MEMS resonator to be −47.4 ppm/°C, in good agreement with the measurements taken by directly probing the resonator
Flexural Plate Wave Piezoelectric MEMS Transducer for Cell Alignment in Aqueous Solution
No full textFlexural Plate Wave Piezoelectric MEMS Transducer for Cell Alignment in Aqueous Solution
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Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
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