scholarly journals Review of Recent Development of MEMS Speakers

Micromachines ◽  
2021 ◽  
Vol 12 (10) ◽  
pp. 1257
Author(s):  
Haoran Wang ◽  
Yifei Ma ◽  
Qincheng Zheng ◽  
Ke Cao ◽  
Yao Lu ◽  
...  
Keyword(s):  
Microelectromechanical Systems ◽  
Low Cost ◽  
Portable Electronics ◽  
Hearing Instruments ◽  
Potential Applications ◽  
Transduction Mechanisms ◽  
Mems Technology ◽  
Small Footprint ◽  
The Internet Of Things ◽  
Made In

Facilitated by microelectromechanical systems (MEMS) technology, MEMS speakers or microspeakers have been rapidly developed during the past decade to meet the requirements of the flourishing audio market. With advantages of a small footprint, low cost, and easy assembly, MEMS speakers are drawing extensive attention for potential applications in hearing instruments, portable electronics, and the Internet of Things (IoT). MEMS speakers based on different transduction mechanisms, including piezoelectric, electrodynamic, electrostatic, and thermoacoustic actuation, have been developed and significant progresses have been made in commercialization in the last few years. In this article, the principle and modeling of each MEMS speaker type is briefly introduced first. Then, the development of MEMS speakers is reviewed with key specifications of state-of-the-art MEMS speakers summarized. The advantages and challenges of all four types of MEMS speakers are compared and discussed. New approaches to improve sound pressure levels (SPLs) of MEMS speakers are also proposed. Finally, the remaining challenges and outlook of MEMS speakers are given.

RF-MEMS Components and Networks for High-Performance Reconfigurable Telecommunication and Wireless Systems

2012 ◽  
Vol 81 ◽  
pp. 65-74 ◽  
Author(s):  
Jacopo Iannacci ◽  
Giuseppe Resta ◽  
Paola Farinelli ◽  
Roberto Sorrentino
Keyword(s):  
High Performance ◽  
Microelectromechanical Systems ◽  
Rf Mems ◽  
Low Cost ◽  
Impedance Matching ◽  
Phase Shifters ◽  
Rf Systems ◽  
Mems Technology ◽  
And Performance ◽  
Rf Performance

MEMS (MicroElectroMechanical-Systems) technology applied to the field of Radio Frequency systems (i.e. RF-MEMS) has emerged in the last 10-15 years as a valuable and viable solution to manufacture low-cost and very high-performance passive components, like variable capacitors, inductors and micro-relays, as well as complex networks, like tunable filters, reconfigurable impedance matching networks and phase shifters, and so on. The availability of such components and their integration within RF systems (e.g. radio transceivers, radars, satellites, etc.) enables boosting the characteristics and performance of telecommunication systems, addressing for instance a significant increase of their reconfigurability. The benefits resulting from the employment of RF-MEMS technology are paramount, being some of them the reduction of hardware redundancy and power consumption, along with the operability of the same RF system according to multiple standards. After framing more in detail the whole context of RF MEMS technology, this paper will provide a brief introduction on a typical RF-MEMS technology platform. Subsequently, some relevant examples of lumped RF MEMS passive elements and complex reconfigurable networks will be reported along with their measured RF performance and characteristics.

scholarly journals MEMS Ultrasound Transducers for Endoscopic Photoacoustic Imaging Applications

Micromachines ◽  
2020 ◽  
Vol 11 (10) ◽  
pp. 928 ◽  
Author(s):  
Haoran Wang ◽  
Yifei Ma ◽  
Hao Yang ◽  
Huabei Jiang ◽  
Yingtao Ding ◽  
...  
Keyword(s):  
Microelectromechanical Systems ◽  
Vibration Mode ◽  
Photoacoustic Imaging ◽  
Rapid Development ◽  
Flexural Vibration ◽  
Ultrasound Transducers ◽  
Optical Contrast ◽  
Future Directions ◽  
Potential Applications ◽  
Mems Technology

Photoacoustic imaging (PAI) is drawing extensive attention and gaining rapid development as an emerging biomedical imaging technology because of its high spatial resolution, large imaging depth, and rich optical contrast. PAI has great potential applications in endoscopy, but the progress of endoscopic PAI was hindered by the challenges of manufacturing and assembling miniature imaging components. Over the last decade, microelectromechanical systems (MEMS) technology has greatly facilitated the development of photoacoustic endoscopes and extended the realm of applicability of the PAI. As the key component of photoacoustic endoscopes, micromachined ultrasound transducers (MUTs), including piezoelectric MUTs (pMUTs) and capacitive MUTs (cMUTs), have been developed and explored for endoscopic PAI applications. In this article, the recent progress of pMUTs (thickness extension mode and flexural vibration mode) and cMUTs are reviewed and discussed with their applications in endoscopic PAI. Current PAI endoscopes based on pMUTs and cMUTs are also introduced and compared. Finally, the remaining challenges and future directions of MEMS ultrasound transducers for endoscopic PAI applications are given.

MEMS Accelerometer Design Optimization Using Genetic Algorithm

2013 ◽  
Vol 705 ◽  
pp. 288-294 ◽  
Author(s):  
V.S. Krushnasamy ◽  
A. Vimala Juliet
Keyword(s):  
Genetic Algorithm ◽  
Design Optimization ◽  
High Efficiency ◽  
Microelectromechanical Systems ◽  
Optimal Parameter ◽  
Low Cost ◽  
Complex Nature ◽  
Mems Accelerometer ◽  
Mems Technology ◽  
Parameter Values

MEMS (Microelectromechanical Systems) refers to the technology integrating electrical and mechanical components with feature size of 1~1000 microns. Due to its small size, low cost, low power consumption and high efficiency, MEMS technology has been widely used in many fields.In this paper,the design optimization of MEMS accelerometer is discussed.The main objective of this investigation is to find a optimum design of MEMS,which satisfies a set of given constraints. The accelerometer employs a double folded beam flexure system and the mass being displaced is the proof mass.Due to the complex nature of the problem,a genetic algorithm (GA) is developed for the optimization of MEMS.The GA attempts to minimize the die area and so the four optimal parameter values can be determined. MEMS accelerometers can be used in air-bag deployment systems in automobiles.The experimental results will show the optimal design of MEMS.

scholarly journals Small Local Earthquake Detection Using Low-Cost MEMS Accelerometers: Examples in Northern and Central Italy

2021 ◽  
Vol 1 (1) ◽  
pp. 20-26
Author(s):  
Valeria Cascone ◽  
Jacopo Boaga ◽  
Giorgio Cassiani
Keyword(s):  
Microelectromechanical Systems ◽  
Detection Efficiency ◽  
Low Cost ◽  
Central Italy ◽  
Mems Sensors ◽  
Earthquake Detection ◽  
Seismicity Monitoring ◽  
Mems Technology ◽  
Local Earthquake ◽  
Accelerometric Network

Abstract This study evaluates the seismicity detection efficiency of a new low-cost triaxial accelerometer prototype based on microelectromechanical systems (MEMS) technology. Networks of MEMS sensors were installed in telecommunication infrastructures to build two small arrays in northern and central Italy. The sensor prototypes recorded major earthquakes as well as nine small seismic events with 2.0<ML<3.0. Where possible, MEMS were compared to the closest high-quality seismic stations belonging to the national accelerometric network. The comparison, in terms of peak ground accelerations and spectral responses, confirms that the signals are in good agreement. The tested inexpensive MEMS sensors were able to detect small local events with epicentral distances as large as 50 km and provided an efficient characterization of the main motion parameters. This confirms that the proposed accelerometer prototypes are promising tools to integrate into traditional networks for local seismicity monitoring.

scholarly journals 3D Printed MEMS Technology—Recent Developments and Applications

Micromachines ◽  
2020 ◽  
Vol 11 (4) ◽  
pp. 434 ◽  
Author(s):  
Tomasz Blachowicz ◽  
Andrea Ehrmann
Keyword(s):  
3D Printing ◽  
Microelectromechanical Systems ◽  
Measurement Technology ◽  
Mems Fabrication ◽  
Recent Developments ◽  
Mems Technology ◽  
New Ideas ◽  
3D Printed ◽  
New Applications ◽  
The Internet Of Things

Microelectromechanical systems (MEMS) are of high interest for recent electronic applications. Their applications range from medicine to measurement technology, from microfluidics to the Internet of Things (IoT). In many cases, MEMS elements serve as sensors or actuators, e.g., in recent mobile phones, but also in future autonomously driving cars. Most MEMS elements are based on silicon, which is not deformed plastically under a load, as opposed to metals. While highly sophisticated solutions were already found for diverse MEMS sensors, actuators, and other elements, MEMS fabrication is less standardized than pure microelectronics, which sometimes blocks new ideas. One of the possibilities to overcome this problem may be the 3D printing approach. While most 3D printing technologies do not offer sufficient resolution for MEMS production, and many of the common 3D printing materials cannot be used for this application, there are still niches in which the 3D printing of MEMS enables producing new structures and thus creating elements for new applications, or the faster and less expensive production of common systems. Here, we give an overview of the most recent developments and applications in 3D printing of MEMS.

scholarly journals Graphene for Flexible Photovoltaic Devices

2019 ◽  
Vol 6 ◽  
Author(s):  
Kwadwo Mensah-Darkwa ◽  
Rita Namoe Tabi ◽  
Pawan K. Kahol ◽  
Ram K. Gupta
Keyword(s):  
Mechanical Stability ◽  
Low Cost ◽  
Optical Transmittance ◽  
Photovoltaic Devices ◽  
Research Attention ◽  
Portable Electronics ◽  
Recent Developments ◽  
Potential Applications ◽  
And Performance ◽  
Generation Technology

Flexible photovoltaic devices (FPD’s) are emerging as next-generation technology in photovoltaic research. FPD’s have attracted great research attention because of their broad potential applications especially in wearable devices, portable electronics, integrated textiles, unmanned aerial vehicles, transportation, and military etc. The existing technologies have evolved over the years, improving efficiency and performance of photovoltaic devices. However, these technologies mostly rely on rigid electrodes that are brittle, costly and chemically unstable. For FPD’s to become practical, new materials that offer inherent flexibility without compromising on mechanical and optical properties must be the focus. Researchers have made significant advances over the past decade towards developing various aspects of FPD’s to improve its optical transmittance, mechanical stability, chemical stability etc. Graphene is increasingly been recognized as an excellent material for flexible photovoltaic devices because of its unique optical, electrical and mechanical properties. The prospects of introducing an inexpensive and abundant carbon-based material such as graphene in making flexible, low-cost, transparent PV cells cannot be over emphasized. However, the method to synthesize graphene to achieve the best performance is still complicated. This paper presents a brief overview of recent developments made in flexible photovoltaic devices using graphene.

Electroactive Polymer Deformable Micromirrors (EAPDM) for Biomedical Optics

2004 ◽  
Vol 820 ◽  
Author(s):  
Cheng Huang ◽  
Bo Bai ◽  
Baojun Chu ◽  
Jim Ding ◽  
Q.M. Zhang
Keyword(s):  
Electric Fields ◽  
High Performance ◽  
Electromechanical Coupling ◽  
Microelectromechanical Systems ◽  
Vinylidene Fluoride ◽  
Low Cost ◽  
Biomedical Optics ◽  
Electroactive Polymer ◽  
Polymer Actuator ◽  
Potential Applications

AbstractElectroactive polymers (EAPs) are capable of converting energy in the form of electric charge and voltage to mechanical force and movement and vice versa. Several electroactive polymer actuator materials whose responses are controlled by external electric fields, e.g. poly(vinylidene fluoride-trifluoroethylene) based fluoroterpolymers, have generated considerable interest for use in applications such as artificial muscles, sensors, parasitic energy capture, integrated bio-microelectromechanical systems (BioMEMS) and microfluidic devices due to their high electric-field induced strain, high elastic modulus, high electromechanical coupling and high frequency operation, etc. Scaling the EAP down into microsystems is one of the promising trends of EAP actuators and sensors especially for biomedical engineering. The combination of micro-optics and integrated BioMEMS, referred to as bio-micro-opto-electromechanical systems (BioMOEMS), makes a new opportunity for innovation in the EAP field. We present an approach to the fabrication of low-cost, large-stroke deformable micromirrors based on high performance electroactive polymer film microactuator arrays. Integrated Optic-BioMEMS based on electroactive polymer deformable micromirror (EAPDM) technology provide potential applications in biomedical optics such as ophthalmology (retinal imaging and vision care) and cancer detection and treatment.

scholarly journals A New Technique for Integrating MEMS-Based Low-Cost IMU and GPS in Vehicular Navigation

2016 ◽  
Vol 2016 ◽  
pp. 1-16 ◽  
Author(s):  
Neda Navidi ◽  
René Jr. Landry ◽  
Jianhua Cheng ◽  
Denis Gingras
Keyword(s):  
Navigation System ◽  
Microelectromechanical Systems ◽  
Fuzzy Inference ◽  
Low Cost ◽  
Integrated System ◽  
Location Based Services ◽  
Inference System ◽  
Stochastic Error ◽  
Stochastic Errors ◽  
Mems Technology

In providing acceptable navigational solutions, Location-Based Services (LBS) in land navigation rely mostly on integration of Global Positioning System (GPS) and Inertial Navigation System (INS) measurements for accuracy and robustness. The GPS/INS integrated system can provide better land-navigation solutions than the ones any standalone system can provide. Low-cost Inertial Measurement Units (IMUs), based on Microelectromechanical Systems (MEMS) technology, revolutionized the land-navigation system by virtue of their low-cost miniaturization and widespread availability. However, their accuracy is strongly affected by their inherent systematic and stochastic errors, which depend mainly on environmental conditions. The environmental noise and nonlinearities prevent obtaining optimal localization estimates in Land Vehicular Navigation (LVN) while using traditional Kalman Filters (KF). The main goal of this paper is to effectively eliminate stochastic errors of MEMS-based IMUs. The proposed solution is divided into two main components: (1) improving noise cancellation, using advanced stochastic error models in MEMS-based IMUs based on combined Autoregressive Processes (ARP) and first-order Gauss-Markov Process (1GMP), and (2) modeling the low-cost GPS/INS integration, using a hybrid Fuzzy Inference System (FIS) and Second-Order Extended Kalman Filter (SOEKF). The results obtained show that the proposed methods perform better than the traditional techniques do in different stochastic and dynamic situations.

DNA Inspirited Rational Construction of Nonconventional Luminophores with Efficient and Color-Tunable Afterglow

2020 ◽  
Author(s):  
Yunzhong Wang ◽  
Saixing Tang ◽  
Yating Wen ◽  
Shuyuan Zheng ◽  
Bing Yang ◽  
...  
Keyword(s):  
Rational Design ◽  
Room Temperature ◽  
Double Helix ◽  
Mechanical Grinding ◽  
Room Temperature Phosphorescence ◽  
Color Tunable ◽  
Potential Applications ◽  
Rational Construction ◽  
Double Helix Structure ◽  
Made In

<div>Persistent room-temperature phosphorescence (p-RTP) from pure organics is attractive </div><div>due to its fundamental importance and potential applications in molecular imaging, </div><div>sensing, encryption, anticounterfeiting, etc.1-4 Recently, efforts have been also made in </div><div>obtaining color-tunable p-RTP in aromatic phosphors5 and nonconjugated polymers6,7. </div><div>The origin of color-tunable p-RTP and the rational design of such luminogens, </div><div>particularly those with explicit structure and molecular packing, remain challenging. </div><div>Noteworthily, nonconventional luminophores without significant conjugations generally </div><div>possess excitation-dependent photoluminescence (PL) because of the coexistence of </div><div>diverse clustered chromophores6,8, which strongly implicates the possibility to achieve </div><div>color-tunable p-RTP from their molecular crystals assisted by effective intermolecular </div><div>interactions. Here, inspirited by the highly stable double-helix structure and multiple </div><div>hydrogen bonds in DNA, we reported a series of nonconventional luminophores based on </div><div>hydantoin (HA), which demonstrate excitation-dependent PL and color-tunable p-RTP </div><div>from sky-blue to yellowish-green, accompanying unprecedentedly high PL and p-RTP </div><div>efficiencies of up to 87.5% and 21.8%, respectively. Meanwhile, the p-RTP emissions are </div><div>resistant to vigorous mechanical grinding, with lifetimes of up to 1.74 s. Such robust, </div><div>color-tunable and highly efficient p-RTP render the luminophores promising for varying </div><div>applications. These findings provide mechanism insights into the origin of color-tunable </div><div>p-RTP, and surely advance the exploitation of efficient nonconventional luminophores.</div>

scholarly journals Bimetallic Ni-Based Catalysts for CO2 Methanation: A Review

Nanomaterials ◽  
2020 ◽  
Vol 11 (1) ◽  
pp. 28
Author(s):  
Anastasios I. Tsiotsias ◽  
Nikolaos D. Charisiou ◽  
Ioannis V. Yentekakis ◽  
Maria A. Goula
Keyword(s):  
Low Temperature ◽  
Noble Metals ◽  
Recent Progress ◽  
Low Cost ◽  
Alloy Formation ◽  
Co2 Methanation ◽  
High Performing ◽  
Mobile Sources ◽  
Low Dispersion ◽  
Made In

CO2 methanation has recently emerged as a process that targets the reduction in anthropogenic CO2 emissions, via the conversion of CO2 captured from point and mobile sources, as well as H2 produced from renewables into CH4. Ni, among the early transition metals, as well as Ru and Rh, among the noble metals, have been known to be among the most active methanation catalysts, with Ni being favoured due to its low cost and high natural abundance. However, insufficient low-temperature activity, low dispersion and reducibility, as well as nanoparticle sintering are some of the main drawbacks when using Ni-based catalysts. Such problems can be partly overcome via the introduction of a second transition metal (e.g., Fe, Co) or a noble metal (e.g., Ru, Rh, Pt, Pd and Re) in Ni-based catalysts. Through Ni-M alloy formation, or the intricate synergy between two adjacent metallic phases, new high-performing and low-cost methanation catalysts can be obtained. This review summarizes and critically discusses recent progress made in the field of bimetallic Ni-M (M = Fe, Co, Cu, Ru, Rh, Pt, Pd, Re)-based catalyst development for the CO2 methanation reaction.

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