scholarly journals Thermal Performance of a Capacitive Comb-Drive MEMS Accelerometer: Measurements vs. Simulation

Energies ◽  
2021 ◽  
Vol 14 (22) ◽  
pp. 7462
Author(s):  
Mariusz Jankowski ◽  
Piotr Zając ◽  
Piotr Amrozik ◽  
Michał Szermer ◽  
Cezary Maj ◽  
...  
Keyword(s):  
Residual Stress ◽  
Thermal Drift ◽  
Readout Circuit ◽  
Temperature Drift ◽  
Comb Drive ◽  
Mems Accelerometer ◽  
Mems Sensor ◽  
Simulation Results ◽  
The Difference ◽  
Capacitive Mems

In this work, we analysed the difference between the measurement and simulation results of thermal drift of a custom designed capacitive MEMS accelerometer. It was manufactured in X-FAB XMB10 technology together with a dedicated readout circuit in X-FAB XP018 technology. It turned out that the temperature sensitivity of the sensor’s output is nonlinear and particularly strong in the negative Celsius temperature range. It was found that the temperature drift is mainly caused by the MEMS sensor and the influence of the readout circuit is minimal. Moreover, the measurements showed that this temperature dependence is the same regardless of applied acceleration. Simulation of the accelerometer’s model allowed us to estimate the contribution of post-manufacturing mismatch on the thermal drift; for our sensor, the mismatch-induced drift accounted for about 6% of total thermal drift. It is argued that the remaining 94% of the drift could be a result of the presence of residual stress in the structure after fabrication.

scholarly journals Temperature Gradient Method for Alleviating Bonding-Induced Warpage in a High-Precision Capacitive MEMS Accelerometer

Sensors ◽  
2020 ◽  
Vol 20 (4) ◽  
pp. 1186
Author(s):  
Dandan Liu ◽  
Huafeng Liu ◽  
Jinquan Liu ◽  
Fangjing Hu ◽  
Ji Fan ◽  
...  
Keyword(s):  
Bonding Temperature ◽  
Displacement Transducer ◽  
Negative Influence ◽  
Mems Accelerometer ◽  
Precise Control ◽  
Electrode Displacement ◽  
Resource Exploration ◽  
The Difference ◽  
Capacitive Mems ◽  
Displacement Transducers

Capacitive MEMS accelerometers with area-variable periodic-electrode displacement transducers found wide applications in disaster monitoring, resource exploration and inertial navigation. The bonding-induced warpage, due to the difference in the coefficients of thermal expansion of the bonded slices, has a negative influence on the precise control of the interelectrode spacing that is essential to the sensitivity of accelerometers. In this work, we propose the theory, simulation and experiment of a method that can alleviate both the stress and the warpage by applying different bonding temperature on the bonded slices. A quasi-zero warpage is achieved experimentally, proving the feasibility of the method. As a benefit of the flat surface, the spacing of the capacitive displacement transducer can be precisely controlled, improving the self-noise of the accelerometer to 6 ng/√Hz @0.07 Hz, which is about two times lower than that of the accelerometer using a uniform-temperature bonding process.

Stiffness Measurement of Micro-Cantilever Based on Negative Electrostatic Stiffness

2020 ◽  
Vol 12 (1) ◽  
pp. 96-100
Author(s):  
Xianshan Dong ◽  
Qinwen Huang ◽  
Yun Huang ◽  
Wei Su ◽  
Ping Lai
Keyword(s):  
Basic Structure ◽  
Mems Devices ◽  
Mechanical Stiffness ◽  
Micro Electro Mechanical Systems ◽  
Mems Accelerometer ◽  
Mems Sensor ◽  
The Difference ◽  
Micro Cantilever ◽  
Fabrication Variation ◽  
Non Destructive

Micro-cantilever is basic structure of Micro-Electro-Mechanical-Systems (MEMS) sensor, and mechanical stiffness is the most important parameter of micro-cantilever. The mechanical stiffness can be affected by shape, size and material, and it should be experimentally measured for fabrication variation. Yet, the micro scale of MEMS cantilever makes the measurement difficult, and the traditional method isn't suitable for the micro-cantilever. This study proposes a new method for measuring the mechanical stiffness of micro-cantilever, and measurement of MEMS accelerometer was also experimentally carried out. The proposed method exploits the feature that the voltage applied on cantilever can lead to negative electrostatic stiffness, and this stiffness can change the deformation of cantilever. The mechanical stiffness can be obtained through analyzing the change of output. Results from this study coincided with our theoretical model, and the difference between results obtained by this method and SEM was 2.2%. This work provides a new way to precisely obtain mechanical stiffness of micro-cantilever using non-destructive method, making it helpful for researchers to design micro-cantilever and MEMS devices.

scholarly journals Capacitive MEMS accelerometer wide range modeling using artificial neural network

2009 ◽  
Vol 7 (02) ◽  
Author(s):  
A. Baharodimehr ◽  
A. Abolfazl Suratgar ◽  
H. Sadeghi
Keyword(s):  
Neural Network ◽  
Artificial Neural Network ◽  
Nonlinear Model ◽  
Mems Accelerometer ◽  
System Parameters ◽  
The Neural Network ◽  
Wide Range ◽  
Levenberg Marquardt ◽  
Simulation Results ◽  
Capacitive Mems

This paper presents a nonlinear model for a capacitive microelectromechanical accelerometer (MEMA). System parameters of the accelerometer are developed using the effect of cubic term of the folded‐flexure spring. To solve this equation, we use the FEA method. The neural network (NN) uses the Levenberg‐Marquardt (LM) method for training the system to have a more accurate response. The designed NN can identify and predict the displacement of the movable mass of accelerometer. The simulation results are very promising.

scholarly journals A Capacitive 3-Axis MEMS Accelerometer for Medipost: A Portable System Dedicated to Monitoring Imbalance Disorders

Sensors ◽  
2021 ◽  
Vol 21 (10) ◽  
pp. 3564
Author(s):  
Michał Szermer ◽  
Piotr Zając ◽  
Piotr Amrozik ◽  
Cezary Maj ◽  
Mariusz Jankowski ◽  
...  
Keyword(s):  
Readout Circuit ◽  
Mems Devices ◽  
Mems Accelerometer ◽  
Patient Movement ◽  
Mems Sensor ◽  
Health Related ◽  
Circuit Integration ◽  
Portable System ◽  
The Impact

The constant development and miniaturization of MEMS sensors invariably provides new possibilities for their use in health-related and medical applications. The application of MEMS devices in posturographic systems allows faster diagnosis and significantly facilitates the work of medical staff. MEMS accelerometers constitute a vital part of such systems, particularly those intended for monitoring patients with imbalance disorders. The correct design of such sensors is crucial for gathering data about patient movement and ensuring the good overall performance of the entire system. This paper presents the design and measurements of a three-axis accelerometer dedicated for use in a device which tracks patient movement. Its main focus is the characterization of the sensor, comparing different designs and evaluating the impact of the packaging and readout circuit integration on sensor operation. Extensive testing and measurements confirm that the designed accelerometer works correctly and allows identifying the best design in terms of sensitivity/stability. Moreover, the response of the proposed sensor as a function of the applied acceleration demonstrates very good linearity only if the readout circuit is integrated in the same package as the MEMS sensor.

TEM investigations of surface residual stress relaxation in A12O3 and Al2O3-SiC nanocomposite

1994 ◽  
Vol 52 ◽  
pp. 628-629
Author(s):  
J. Fang ◽  
H. M. Chan ◽  
M. P. Harmer
Keyword(s):  
Residual Stress ◽  
Single Phase ◽  
Stress Relief ◽  
Stress Recovery ◽  
Surface Residual Stress ◽  
Microscopic Mechanism ◽  
Sic Particles ◽  
Annealing Procedure ◽  
The Difference ◽  
Nano Size

It was Niihara et al. who first discovered that the fracture strength of Al2O3 can be increased by incorporating as little as 5 vol.% of nano-size SiC particles (>1000 MPa), and that the strength would be improved further by a simple annealing procedure (>1500 MPa). This discovery has stimulated intense interest on Al2O3/SiC nanocomposites. Recent indentation studies by Fang et al. have shown that residual stress relief was more difficult in the nanocomposite than in pure Al2O3. In the present work, TEM was employed to investigate the microscopic mechanism(s) for the difference in the residual stress recovery in these two materials.Bulk samples of hot-pressed single phase Al2O3, and Al2O3 containing 5 vol.% 0.15 μm SiC particles were simultaneously polished with 15 μm diamond compound. Each sample was cut into two pieces, one of which was subsequently annealed at 1300° for 2 hours in flowing argon. Disks of 3 mm in diameter were cut from bulk samples.

Modulation instability in nonlinear chiral fiber

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Demissie Jobir Gelmecha ◽  
Ram Sewak Singh
Keyword(s):  
Theoretical Model ◽  
Numerical Simulations ◽  
Pulse Propagation ◽  
Modulation Instability ◽  
Constitutive Relations ◽  
Gain Spectrum ◽  
Circularly Polarized ◽  
Left Handed ◽  
Simulation Results ◽  
The Difference

AbstractIn this paper, the rigorous derivations of generalized coupled chiral nonlinear Schrödinger equations (CCNLSEs) and their modulation instability analysis have been explored theoretically and computationally. With the consideration of Maxwell’s equations and Post’s constitutive relations, a generalized CCNLSE has been derived, which describes the evolution of left-handed circularly polarized (LCP) and right-handed circularly polarized (RCP) components propagating through single-core nonlinear chiral fiber. The analysis of modulation instability in nonlinear chiral fiber has been investigated starting from CCNLSEs. Based on a theoretical model and numerical simulations, the difference on the modulation instability gain spectrum in LCP and RCP components through chiral fiber has been analyzed by considering loss and chirality into account. The obtained simulation results have shown that the loss distorts the sidebands of the modulation instability gain spectrum, while chirality modulates the gain for LCP and RCP components in a different manner. This suggests that adjusting chirality strength may control the loss, and nonlinearity simultaneously provides stable modulated pulse propagation.

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