scholarly journals Monolithic Multi Degree of Freedom (MDoF) Capacitive MEMS Accelerometers

Micromachines ◽  
2018 ◽  
Vol 9 (11) ◽  
pp. 602 ◽  
Author(s):  
Zakriya Mohammed ◽  
Ibrahim Elfadel ◽  
Mahmoud Rasras
Keyword(s):  
Microelectromechanical Systems ◽  
Inertial Sensors ◽  
Electrical Contact ◽  
High Sensitivity ◽  
Low Noise ◽  
Degree Of Freedom ◽  
Noise Floor ◽  
Mems Accelerometers ◽  
Capacitive Mems ◽  
Cross Axis

With the continuous advancements in microelectromechanical systems (MEMS) fabrication technology, inertial sensors like accelerometers and gyroscopes can be designed and manufactured with smaller footprint and lower power consumption. In the literature, there are several reported accelerometer designs based on MEMS technology and utilizing various transductions like capacitive, piezoelectric, optical, thermal, among several others. In particular, capacitive accelerometers are the most popular and highly researched due to several advantages like high sensitivity, low noise, low temperature sensitivity, linearity, and small footprint. Accelerometers can be designed to sense acceleration in all the three directions (X, Y, and Z-axis). Single-axis accelerometers are the most common and are often integrated orthogonally and combined as multiple-degree-of-freedom (MDoF) packages for sensing acceleration in the three directions. This type of MDoF increases the overall device footprint and cost. It also causes calibration errors and may require expensive compensations. Another type of MDoF accelerometers is based on monolithic integration and is proving to be effective in solving the footprint and calibration problems. There are mainly two classes of such monolithic MDoF accelerometers, depending on the number of proof masses used. The first class uses multiple proof masses with the main advantage being zero calibration issues. The second class uses a single proof mass, which results in compact device with a reduced noise floor. The latter class, however, suffers from high cross-axis sensitivity. It also requires very innovative layout designs, owing to the complicated mechanical structures and electrical contact placement. The performance complications due to nonlinearity, post fabrication process, and readout electronics affects both classes of accelerometers. In order to effectively compare them, we have used metrics such as sensitivity per unit area and noise-area product. This paper is devoted to an in-depth review of monolithic multi-axis capacitive MEMS accelerometers, including a detailed analysis of recent advancements aimed at solving their problems such as size, noise floor, cross-axis sensitivity, and process aware modeling.

scholarly journals Design Approaches of MEMS Microphones for Enhanced Performance

2019 ◽  
Vol 2019 ◽  
pp. 1-26 ◽  
Author(s):  
Muhammad Ali Shah ◽  
Ibrar Ali Shah ◽  
Duck-Gyu Lee ◽  
Shin Hur
Keyword(s):  
Research Work ◽  
Single Crystal Silicon ◽  
High Sensitivity ◽  
Low Noise ◽  
Crystal Silicon ◽  
Mems Microphone ◽  
Mems Microphones ◽  
Improved Performance ◽  
Capacitive Mems ◽  
Omnidirectional Microphones

This paper reports a review about microelectromechanical system (MEMS) microphones. The focus of this review is to identify the issues in MEMS microphone designs and thoroughly discuss the state-of-the-art solutions that have been presented by the researchers to improve performance. Considerable research work has been carried out in capacitive MEMS microphones, and this field has attracted the research community because these designs have high sensitivity, flat frequency response, and low noise level. A detailed overview of the omnidirectional microphones used in the applications of an audio frequency range has been presented. Since the microphone membrane is made of a thin film, it has residual stress that degrades the microphone performance. An in-depth detailed review of research articles containing solutions to relieve these stresses has been presented. The comparative analysis of fabrication processes of single- and dual-chip omnidirectional microphones, in which the membranes are made up of single-crystal silicon, polysilicon, and silicon nitride, has been done, and articles containing the improved performance in these two fabrication processes have been explained. This review will serve as a starting guide for new researchers in the field of capacitive MEMS microphones.

Design of Perforated Membrane for Low-Noise Capacitive MEMS Accelerometers

2018 ◽  
Author(s):  
Atsushi Isobe ◽  
Yudai Kamada ◽  
Takashi Oshima ◽  
Yuki Furubayashi ◽  
Noriyuki Sakuma ◽  
...  
Keyword(s):  
Low Noise ◽  
Mems Accelerometers ◽  
Capacitive Mems

Design of Perforated Membrane for Low-Noise Capacitive MEMS Accelerometers

2020 ◽  
Vol 20 (3) ◽  
pp. 1184-1190 ◽  
Author(s):  
Atsushi Isobe ◽  
Yudai Kamada ◽  
Chisaki Takubo ◽  
Yuki Furubayashi ◽  
Takashi Oshima ◽  
...  
Keyword(s):  
Low Noise ◽  
Mems Accelerometers ◽  
Capacitive Mems

scholarly journals Random Error Reduction Algorithms for MEMS Inertial Sensor Accuracy Improvement—A Review

Micromachines ◽  
2020 ◽  
Vol 11 (11) ◽  
pp. 1021
Author(s):  
Shipeng Han ◽  
Zhen Meng ◽  
Olatunji Omisore ◽  
Toluwanimi Akinyemi ◽  
Yuepeng Yan
Keyword(s):  
Random Error ◽  
Microelectromechanical Systems ◽  
Inertial Sensors ◽  
Inertial Sensor ◽  
Random Noise ◽  
Development Trend ◽  
Sensor Technology ◽  
Application Range ◽  
Mems Accelerometers ◽  
Mems Gyroscopes

Research and industrial studies have indicated that small size, low cost, high precision, and ease of integration are vital features that characterize microelectromechanical systems (MEMS) inertial sensors for mass production and diverse applications. In recent times, sensors like MEMS accelerometers and MEMS gyroscopes have been sought in an increased application range such as medical devices for health care to defense and military weapons. An important limitation of MEMS inertial sensors is repeatedly documented as the ease of being influenced by environmental noise from random sources, along with mechanical and electronic artifacts in the underlying systems, and other random noise. Thus, random error processing is essential for proper elimination of artifact signals and improvement of the accuracy and reliability from such sensors. In this paper, a systematic review is carried out by investigating different random error signal processing models that have been recently developed for MEMS inertial sensor precision improvement. For this purpose, an in-depth literature search was performed on several databases viz., Web of Science, IEEE Xplore, Science Direct, and Association for Computing Machinery Digital Library. Forty-nine representative papers that focused on the processing of signals from MEMS accelerometers, MEMS gyroscopes, and MEMS inertial measuring units, published in journal or conference formats, and indexed on the databases within the last 10 years, were downloaded and carefully reviewed. From this literature overview, 30 mainstream algorithms were extracted and categorized into seven groups, which were analyzed to present the contributions, strengths, and weaknesses of the literature. Additionally, a summary of the models developed in the studies was presented, along with their working principles viz., application domain, and the conclusions made in the studies. Finally, the development trend of MEMS inertial sensor technology and its application prospects were presented.

scholarly journals Design Approach for Reducing Cross-Axis Sensitivity in a Single-Drive Multi-Axis MEMS Gyroscope

Micromachines ◽  
2021 ◽  
Vol 12 (8) ◽  
pp. 902
Author(s):  
Hussamud Din ◽  
Faisal Iqbal ◽  
Byeungleul Lee
Keyword(s):  
Microelectromechanical Systems ◽  
Reduction Rate ◽  
Design Technique ◽  
Matching Method ◽  
Mems Gyroscope ◽  
Mode Split ◽  
The Cross ◽  
The Individual ◽  
Cross Axis ◽  
Ratio Matching

In this paper, a new design technique is presented to estimate and reduce the cross-axis sensitivity (CAS) in a single-drive multi-axis microelectromechanical systems (MEMS) gyroscope. A simplified single-drive multi-axis MEMS gyroscope, based on a mode-split approach, was analyzed for cross-axis sensitivity using COMSOL Multiphysics. A design technique named the “ratio-matching method” of drive displacement amplitudes and sense frequency differences ratios was proposed to reduce the cross-axis sensitivity. Initially, the cross-axis sensitivities in the designed gyroscope for x and y-axis were calculated to be 0.482% and 0.120%, respectively, having an average CAS of 0.301%. Using the proposed ratio-matching method and design technique, the individual cross-axis sensitivities in the designed gyroscope for x and y-axis were reduced to 0.018% and 0.073%, respectively. While the average CAS was reduced to 0.045%, showing a reduction rate of 85.1%. Moreover, the proposed ratio-matching method for cross-axis sensitivity reduction was successfully validated through simulations by varying the coupling spring position and sense frequency difference variation analyses. Furthermore, the proposed methodology was verified experimentally using fabricated single-drive multi-axis gyroscope.

High sensitivity, low noise Mirnov coil array on Prairie View rotamak

2012 ◽  
Vol 83 (10) ◽  
pp. 10E304 ◽  
Author(s):  
X. Yang ◽  
S. Houshmandyar ◽  
O. Dada ◽  
E. Reddic ◽  
T. S. Huang
Keyword(s):  
High Sensitivity ◽  
Low Noise ◽  
Coil Array
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