Dual-Resonator-Based (DRB) and Multiple-Resonator-Based (MRB) MEMS Sensors: A Review

Single-resonator-based (SRB) sensors have thrived in many sensing applications. However, they cannot meet the high-sensitivity requirement of future high-end markets such as ultra-small mass sensors and ultra-low accelerometers, and are vulnerable to environmental influences. It is fortunate that the integration of dual or multiple resonators into a sensor has become an effective way to solve such issues. Studies have shown that dual-resonator-based (DRB) and multiple-resonator-based (MRB) MEMS sensors have the ability to reject environmental influences, and their sensitivity is tens or hundreds of times that of SRB sensors. Hence, it is worth understanding the state-of-the-art technology behind DRB and MRB MEMS sensors to promote their application in future high-end markets.

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Nonlinear Behavior of a Parametric Resonance-Based Mass Sensor

Microelectromechanical Systems ◽

10.1115/imece2002-33261 ◽

2002 ◽

Cited By ~ 4

Author(s):

Wenhua Zhang ◽

Rajashree Baskaran ◽

Kimberly L. Turner

Keyword(s):

Parametric Resonance ◽

Mathieu Equation ◽

Nonlinear Behavior ◽

High Sensitivity ◽

Small Mass ◽

Mass Change ◽

Mass Sensor ◽

Mass Sensors ◽

Mems Oscillator ◽

Harmonic Resonance

The ability to detect mass change of the order of femtograms (10e-15g) opens up implementations of various precise chemical and biological sensors. Micro-scale oscillator based mass sensors are promising due to their small mass and high sensitivity. Many such sensors detect mass change by measuring the shift of natural frequency. We have reported previous work introducing the idea of using parametric resonance to detect mass change. This method utilizes stability behavior with mass variation as the detection criterion and high sensitivity is expected. This paper presents theoretical and experimental research on nonlinearity effects on the dynamic behavior of a MEMS oscillator, which is the prototype of such a mass sensor. A Duffing equation and a nonlinear Mathieu equation are used to model the behavior of nonlinear harmonic resonance and parametric resonance. Experimental results agree with the theoretical analysis very well. Some bulk equivalent parameters, such as Q factor, cubic stiffness and linear electrostatic stiffness can be estimated by studying the nonlinear behavior. The estimation of the parameters is important for design of the optimal mass sensor. The potential effects of nonlinearity on mass sensor application are discussed.

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The state-of-the-art of “high-sensitivity” immunoassay for measuring cardiac troponin I and T

Journal of Laboratory and Precision Medicine ◽

10.21037/jlpm.2018.05.04 ◽

2018 ◽

Vol 3 ◽

pp. 53-53 ◽

Cited By ~ 6

Author(s):

Aldo Clerico ◽

Giuseppe Lippi

Keyword(s):

Cardiac Troponin ◽

Troponin I ◽

State Of The Art ◽

High Sensitivity ◽

Cardiac Troponin I ◽

The State

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Exploring Multiple Antennas for Long-range WiFi Sensing

Proceedings of the ACM on Interactive Mobile Wearable and Ubiquitous Technologies ◽

10.1145/3494979 ◽

2021 ◽

Vol 5 (4) ◽

pp. 1-30

Author(s):

Youwei Zeng ◽

Jinyi Liu ◽

Jie Xiong ◽

Zhaopeng Liu ◽

Dan Wu ◽

...

Keyword(s):

Long Range ◽

State Of The Art ◽

Multiple Antennas ◽

The State ◽

Coarse Grained ◽

Human Walking ◽

Sensing Range ◽

Sensing Applications ◽

Human Respiration ◽

Reflected Signal

Despite extensive research effort on contactless WiFi sensing over the past few years, there are still significant barriers hindering its wide application. One key issue is the limited sensing range due to the intrinsic nature of employing the weak target-reflected signal for sensing and therefore the sensing range is much smaller than the communication range. In this work, we address this challenging issue, moving WiFi sensing one step closer to real-world adoption. The key idea is to effectively utilize the multiple antennas widely available on commodity WiFi access points to simultaneously strengthen the target-reflected signal and reduce the noise. Although traditional beamforming schemes can help increase the signal strength, they are designed for communication and can not be directly applied to benefit sensing. To effectively increase the WiFi sensing range using multiple antennas, we first propose a new metric that quantifies the signal sensing capability. We then propose novel signal processing methods, which lay the theoretical foundation to support beamforming-based long-range WiFi sensing. To validate the proposed idea, we develop two sensing applications: fine-grained human respiration monitoring and coarse-grained human walking tracking. Extensive experiments show that: (i) the human respiration sensing range is significantly increased from the state-of-the-art 6-8 m to 11 m;1 and (ii) human walking can be accurately tracked even when the target is 18 m away from the WiFi transceivers, outperforming the sensing range of the state-of-the-art by 50%.

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Practical Picture Processing

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100051700 ◽

1974 ◽

Vol 32 ◽

pp. 338-339

Author(s):

T. A. Welton

Keyword(s):

Radiation Damage ◽

Coherence Length ◽

Spatial Information ◽

State Of The Art ◽

Coherent Radiation ◽

The State ◽

Energy Spread ◽

Electron Micrograph ◽

Picture Processing ◽

Molecular Skeleton

Various authors have emphasized the spatial information resident in an electron micrograph taken with adequately coherent radiation. In view of the completion of at least one such instrument, this opportunity is taken to summarize the state of the art of processing such micrographs. We use the usual symbols for the aberration coefficients, and supplement these with £ and 6 for the transverse coherence length and the fractional energy spread respectively. He also assume a weak, biologically interesting sample, with principal interest lying in the molecular skeleton remaining after obvious hydrogen loss and other radiation damage has occurred.

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