scholarly journals Fabrication of MEMS Directional Acoustic Sensors for Underwater Operation

Sensors ◽  
2020 ◽  
Vol 20 (5) ◽  
pp. 1245
Author(s):  
Alberto Espinoza ◽  
Fabio Alves ◽  
Renato Rabelo ◽  
German Da Re ◽  
Gamani Karunasiri
Keyword(s):  
Resonant Frequency ◽  
Microelectromechanical Systems ◽  
Mechanical Response ◽  
Silicone Oil ◽  
Signal To Noise Ratio ◽  
Acoustic Sensors ◽  
Mems Sensors ◽  
Free Standing ◽  
Comb Finger ◽  
Narrow Frequency Band

In this work, microelectromechanical systems (MEMS)-based directional acoustic sensors operating in an underwater environment are explored. The studied sensors consist of a free-standing single wing or two wings pivoted to a substrate. The sensors operate in a narrow frequency band determined by the resonant frequency of the mechanical structure. The electronic readout of the mechanical response is obtained using interdigitated comb finger capacitors attached to the wings. The characteristics of MEMS sensors immersed in silicone oil are simulated using finite element modeling. The performance of the sensors is evaluated both in air and underwater. For underwater testing and operation, the sensors are packaged in a housing containing silicone oil, which was specially developed to present near unity acoustic transmission. The measurements show that the resonant frequency of the sensors obtained in air shifts to a lower frequency when immersed in silicone oil, which is primarily due to the mass loading of the liquid. The peak sensitivity of the MEMS sensors is approximately 6 mV/Pa or −165 dB re 1 V/μPa, and the directional response shows a dipole pattern. The signal-to-noise ratio was found to be about 200 or 23 dB at 1 Pa incident sound pressure. The results show the potential of MEMS sensors to be used in underwater applications for sound source localization.

Feasibility Study of a Capacitive MEMS Filter Using Electrostatic Levitation

2019 ◽  
Author(s):  
Mark Pallay ◽  
Shahrzad Towfighian
Keyword(s):  
Mechanical Response ◽  
Filter Design ◽  
Signal To Noise Ratio ◽  
Capacitive Sensor ◽  
Electrostatic Levitation ◽  
Plate Electrode ◽  
System A ◽  
Capacitive Mems ◽  
Mems Filter ◽  
Large Output

Abstract We introduce a capacitive MEMS filter that uses electrostatic levitation for actuation and sensing. The advantage of this electrode configuration is that it does not suffer from the pull-in instability and therefore tremendously high voltages can be applied to this system. A large sensing voltage will produce a large output signal, which boosts the signal to noise ratio. The filter outputs about a 110mV peak-to-peak signal when operated at 175V, and can be boosted to 175mV by increasing the voltage to 250V. Because pull-in is eliminated, voltages much higher than 250V can be applied. An outline of the filter design and operating principle is discussed. A model of the filter is derived and analyzed to show the mechanical response and approximate peak-to-peak signal output. This study shows the feasibility of a capacitive sensor that is based on electrostatic levitation, and outlines the advantages it has over traditional parallel-plate electrode configurations. This design is promising for signal signal processing applications where large strokes are important.

scholarly journals Design and fabrication of a microelectromechanical system resonator based on two orthogonal silicon beams with integrated mirror for monitoring in-plane magnetic field

2019 ◽  
Vol 11 (7) ◽  
pp. 168781401985368 ◽  
Author(s):  
Jesús Acevedo-Mijangos ◽  
Antonio Ramírez-Treviño ◽  
Daniel A May-Arrioja ◽  
Patrick LiKamWa ◽  
Héctor Vázquez-Leal ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Finite Element Method ◽  
Finite Element ◽  
Resonant Frequency ◽  
Microelectromechanical Systems ◽  
Analytical Models ◽  
Complex Signal ◽  
Bending Vibration ◽  
Element Method ◽  
Silicon Beams

We present a resonant magnetic field sensor based on microelectromechanical systems technology with optical detection. The sensor has single resonator composed of two orthogonal silicon beams (600 µm × 26 µm × 2 µm) with an integrated mirror (50 µm × 34 µm × 0.11 µm) and gold tracks (16 µm × 0.11 µm). The resonator is fabricated using silicon-on-insulator wafer in a simple bulk micromachining process. The sensor has easy performance that allows its oscillation in the first bending vibration mode through the Lorentz force for monitoring in-plane magnetic field. Analytical models are developed to predict first bending resonant frequency, quality factor, and displacements of the resonator. In addition, finite element method models are obtained to estimate the resonator performance. The results of the proposed analytical models agree well with those of the finite element method models. For alternating electrical current of 30 mA, the sensor has a theoretical linear response, a first bending resonant frequency of 43.8 kHz, a sensitivity of 46.1 µm T−1, and a power consumption close to 54 mW. The experimental resonant frequency of the sensor is 53 kHz. The proposed sensor could be used for monitoring in-plane magnetic field without a complex signal conditioning system.

scholarly journals Simulations and Experiments on the Vibrational Characteristics of Cylindrical Shell Resonator Actuated by Piezoelectric Electrodes with Different Thicknesses

2017 ◽  
Vol 2017 ◽  
pp. 1-6 ◽  
Author(s):  
Yiming Luo ◽  
Tianliang Qu ◽  
Bin Zhang ◽  
Yao Pan ◽  
Pengbo Xiao
Keyword(s):  
Cylindrical Shell ◽  
Resonant Frequency ◽  
Signal To Noise Ratio ◽  
Great Influence ◽  
Element Model ◽  
Vibrational Amplitude ◽  
Driving Voltage ◽  
Electrode Thickness ◽  
Resonant Frequencies ◽  
Vibrational Characteristics

The resonator is the key element of the Coriolis Vibratory Gyroscope (CVG). The vibrational characteristics of the resonator, including the resonant frequency, vibrational amplitude, and Q factor, have a great influence on CVG’s performance. Among them, the vibrational amplitude mainly affects the scale factor and the signal-to-noise ratio, and the Q factor directly determines the precision and drift characteristics of the gyroscope. In this paper, a finite element model of a cylindrical shell resonator actuated by piezoelectric electrodes with different thicknesses is built to investigate the vibrational characteristics. The simulation results indicate that the resonant frequency barely changes with the electrode thickness, whereas the vibrational amplitude is inversely proportional to the electrode thickness under the same driving voltage. Experiments were performed with four resonators and piezoelectric electrodes of four sizes, and results were consistent with simulations. The resonant frequencies of four resonators changed within 0.36% after attaching the piezoelectric electrodes. Meanwhile, with the same driving voltage, it was shown that the vibrational amplitude decreased with the increase of electrode thickness. Moreover, thinner electrodes resulted in better Q factor and therefore better performance. This study may provide useful reference on electrode design of the CVGs.

Ultrathin Free-Standing Polymer Films Deposited onto Patterned Ionic Liquids and Silicone Oil

2011 ◽  
Vol 45 (1) ◽  
pp. 165-170 ◽  
Author(s):  
Robert J. Frank-Finney ◽  
Patrick D. Haller ◽  
Malancha Gupta
Keyword(s):  
Ionic Liquids ◽  
Polymer Films ◽  
Silicone Oil ◽  
Free Standing

scholarly journals Quantitative Mapping of Free-Standing Lipid Membranes on Nano-Porous Mica Substrates

2018 ◽  
Author(s):  
Luca Costa ◽  
Adrian Carretero-Genevrier ◽  
Etienne Ferrain ◽  
Pierre-Emmanuel Milhiet ◽  
Laura Picas
Keyword(s):  
Lipid Membranes ◽  
Mechanical Response ◽  
Mechanical Stability ◽  
Biological Membranes ◽  
Chemical Properties ◽  
Elastic Response ◽  
Free Standing ◽  
Bending Modulus ◽  
Quantitative Mapping ◽  
Cell Adhesion And Migration

ABSTRACTThe physic-chemistry of biological membranes is at the origin of fundamental cellular functions such as vesicle trafficking, cell adhesion and migration1-3. Because most of intracellular shapes and local demixing of membranes take place in the nanometer scale, AFM becomes an extremely powerful technique to assess the properties of these biological membranes. Porous substrates provide an elegant strategy to avoid the conundrum of placing soft and thin biomembranes on hard substrates for AFM studies, although the surface chemistry make the actual substrates rather challenging setups. Here, we have engineered porous systems on the most widely used substrate in AFM, mica muscovite, with tunable pore sizes from some tens to few hundreds nanometers for biological applications. We show that free-standing bilayers on nano-porous can be obtained by using well-established vesicle spreading methods and that they display equivalent nano-mechanical stability and phsyco-chemical properties to that of membranes on conventional mica supports. By reducing the pore radius < 40 nm and limiting the contribution of membrane tension to the elastic response of free-standing membranes we estimate a bending modulus of 18 kbT and 73 kbT for DOPC and DPPC bilayers, respectively. The quantitative mapping of suspended membranes shows a different mechanical response at the pore rims, which is more pronounced for DPPC and suggest a different lipid ordering. We find that the combination of membrane bending and the different lipid packing at the edges of pores shapes the curvature of free-standing membranes on pores in the range of few tens of nm.

scholarly journals Active Magnetoelectric Motion Sensing: Examining Performance Metrics with an Experimental Setup

Sensors ◽  
2021 ◽  
Vol 21 (23) ◽  
pp. 8000
Author(s):  
Johannes Hoffmann ◽  
Eric Elzenheimer ◽  
Christin Bald ◽  
Clint Hansen ◽  
Walter Maetzler ◽  
...  
Keyword(s):  
Performance Metrics ◽  
Signal To Noise Ratio ◽  
Bandwidth Selection ◽  
Movement Analysis ◽  
Motion Sensing ◽  
Distributed Sensors ◽  
Limited Bandwidth ◽  
Narrow Frequency Band ◽  
Prospective Application ◽  
Novel Concept

Magnetoelectric (ME) sensors with a form factor of a few millimeters offer a comparatively low magnetic noise density of a few pT/Hz in a narrow frequency band near the first bending mode. While a high resonance frequency (kHz range) and limited bandwidth present a challenge to biomagnetic measurements, they can potentially be exploited in indirect sensing of non-magnetic quantities, where artificial magnetic sources are applicable. In this paper, we present the novel concept of an active magnetic motion sensing system optimized for ME sensors. Based on the signal chain, we investigated and quantified key drivers of the signal-to-noise ratio (SNR), which is closely related to sensor noise and bandwidth. These considerations were demonstrated by corresponding measurements in a simplified one-dimensional motion setup. Accordingly, we introduced a customized filter structure that enables a flexible bandwidth selection as well as a frequency-based separation of multiple artificial sources. Both design goals target the prospective application of ME sensors in medical movement analysis, where a multitude of distributed sensors and sources might be applied.

scholarly journals The Influence of Soccer Playing Surface on the Loading Response to Ankle (P)Rehabilitation Exercises

2021 ◽  
Vol 30 (1) ◽  
pp. 105-111
Author(s):  
Adam Jones ◽  
Chris Brogden ◽  
Richard Page ◽  
Ben Langley ◽  
Matt Greig
Keyword(s):  
Global Positioning System ◽  
Repeated Measures ◽  
Microelectromechanical Systems ◽  
Mechanical Response ◽  
Ankle Injury ◽  
Positioning System ◽  
Increased Risk ◽  
Global Positioning ◽  
Rehabilitation Exercises

Context: Contemporary synthetic playing surfaces have been associated with an increased risk of ankle injury in the various types of football. Triaxial accelerometers facilitate in vivo assessment of planar mechanical loading on the player. Objective: To quantify the influence of playing surface on the PlayerLoad elicited during footwork and plyometric drills focused on the mechanism of ankle injury. Design: Repeated-measures, field-based design. Setting: Regulation soccer pitches. Participants: A total of 15 amateur soccer players (22.1 [2.4] y), injury free with ≥6 years competitive experience. Interventions: Each player completed a test battery comprising 3 footwork drills (anterior, lateral, and diagonal) and 4 plyometric drills (anterior hop, inversion hop, eversion hop, and diagonal hop) on natural turf (NT), third-generation artificial turf (3G), and AstroTurf. Global positioning system sensors were located at C7 and the mid-tibia of each leg to measure triaxial acceleration (100 Hz). Main Outcome Measures: PlayerLoad in each axial plane was calculated for each drill on each surface and at each global positioning system location. Results: Analysis of variance revealed a significant main effect for sensor location in all drills, with PlayerLoad higher at mid-tibia than at C7 in all movement planes. AstroTurf elicited significantly higher PlayerLoad in the mediolateral and anteroposterior planes, with typically no difference between NT and 3G. In isolated inversion and eversion hopping trials, the 3G surface also elicited lower PlayerLoad than NT. Conclusions: PlayerLoad magnitude was sensitive to unit placement, advocating measurement with greater anatomical relevance when using microelectromechanical systems technology to monitor training or rehabilitation load. AstroTurf elicited higher PlayerLoad across all planes and drills and should be avoided for rehabilitative purposes, whereas 3G elicited a similar mechanical response to NT.

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