scholarly journals Mechanical Synchronization of MEMS Electrostatically Driven Coupled Beam Filters

Micromachines ◽  
2021 ◽  
Vol 12 (10) ◽  
pp. 1191
Author(s):  
Richard Syms ◽  
Adam Bouchaala
Keyword(s):  
High Performance ◽  
Element Model ◽  
Finite Element Models ◽  
Q Factor ◽  
Exact Mass ◽  
High Q ◽  
Lumped Element ◽  
Lumped Element Model ◽  
Coupled Beams ◽  
Spurious Modes

Micro-electromechanical systems (MEMS) bandpass filters based on arrays of electrostatically driven coupled beams have been demonstrated at MHz frequencies. High performance follows from the high Q-factor of mechanical resonators, and electrostatic transduction allows tuning, matching and actuation. For high-order filters, there is a conflict between the transduction mechanism and the coupling arrangement needed for dynamic synchronization: it is not possible to achieve synchronization and tuning simultaneously using a single voltage. Here we propose a general solution, based on the addition of mass-loaded beams at the ends of the array. These beams deflect for direct current (DC) voltages, and therefore allow electrostatic tuning, but do not respond to in-band alternating current (AC) voltages and hence do not interfere with synchronization. Spurious modes generated by these beams may be damped, leaving a good approximation to the desired response. The approach is introduced using a lumped element model and verified using stiffness matrix and finite element models for in-plane arrays with parallel plate drives and shown to be tolerant of the exact mass value. The principle may allow compensation of fabrication-induced variations in complex filters.

scholarly journals New architectures for micromechanical coupled beam array filters

2020 ◽  
Author(s):  
A. Bouchaala ◽  
R. R. A. Syms
Keyword(s):  
High Performance ◽  
Microelectromechanical Systems ◽  
Wave Theory ◽  
Element Model ◽  
Rapid Identification ◽  
Plane Motion ◽  
Design Parameters ◽  
Lumped Element ◽  
Beam Array ◽  
Lumped Element Model

AbstractCoupled resonator filters implemented as microelectromechanical systems (MEMS) offer performance advantages as band-pass filters at MHz frequencies. Here new designs based on resonant cavities for acoustic slow waves are developed to allow alternative frequency responses. Derivation of the lumped element model for coupled beam systems with in-plane motion from Rayleigh–Ritz perturbation theory is first reviewed. Departures from ideal behaviour caused by mechanical and electrostatic detuning are resolved. Slow wave theory is then used to develop linear array topologies with novel responses including band-stop and comb filtering with controlled filter roll-off. A systematic procedure is developed to allow rapid identification of design parameters without the need for lengthy numerical simulation, using the lumped element, stiffness matrix and finite element methods to investigate the layout parameters of initial design concepts, detailed mechanical effects and detailed electrostatic effects, respectively. High performance is demonstrated, with good agreement between the models.

scholarly journals A computationally efficient hybrid 2D–3D subwoofer model

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Ahmad H. Bokhari ◽  
Martin Berggren ◽  
Daniel Noreland ◽  
Eddie Wadbro
Keyword(s):  
Hybrid Model ◽  
3D Model ◽  
Element Model ◽  
Acoustic Properties ◽  
Computational Time ◽  
Average Response ◽  
Frequency Range ◽  
Computationally Efficient ◽  
Lumped Element ◽  
Lumped Element Model

AbstractA subwoofer generates the lowest frequency range in loudspeaker systems. Subwoofers are used in audio systems for live concerts, movie theatres, home theatres, gaming consoles, cars, etc. During the last decades, numerical simulations have emerged as a cost- and time-efficient complement to traditional experiments in the design process of different products. The aim of this study is to reduce the computational time of simulating the average response for a given subwoofer design. To this end, we propose a hybrid 2D–3D model that reduces the computational time significantly compared to a full 3D model. The hybrid model describes the interaction between different subwoofer components as interacting modules whose acoustic properties can partly be pre-computed. This allows us to efficiently compute the performance of different subwoofer design layouts. The results of the hybrid model are validated against both a lumped element model and a full 3D model over a frequency band of interest. The hybrid model is found to be both accurate and computationally efficient.

scholarly journals A general theory of glacier surges

2019 ◽  
Vol 65 (253) ◽  
pp. 701-716 ◽  
Author(s):  
D. I. Benn ◽  
A. C. Fowler ◽  
I. Hewitt ◽  
H. Sevestre
Keyword(s):  
General Theory ◽  
Frictional Heating ◽  
Element Model ◽  
Geothermal Heating ◽  
Lumped Element ◽  
Systems Model ◽  
Flow Speeds ◽  
Glacier Surges ◽  
Lumped Element Model ◽  
Polythermal Glacier

AbstractWe present the first general theory of glacier surging that includes both temperate and polythermal glacier surges, based on coupled mass and enthalpy budgets. Enthalpy (in the form of thermal energy and water) is gained at the glacier bed from geothermal heating plus frictional heating (expenditure of potential energy) as a consequence of ice flow. Enthalpy losses occur by conduction and loss of meltwater from the system. Because enthalpy directly impacts flow speeds, mass and enthalpy budgets must simultaneously balance if a glacier is to maintain a steady flow. If not, glaciers undergo out-of-phase mass and enthalpy cycles, manifest as quiescent and surge phases. We illustrate the theory using a lumped element model, which parameterizes key thermodynamic and hydrological processes, including surface-to-bed drainage and distributed and channelized drainage systems. Model output exhibits many of the observed characteristics of polythermal and temperate glacier surges, including the association of surging behaviour with particular combinations of climate (precipitation, temperature), geometry (length, slope) and bed properties (hydraulic conductivity). Enthalpy balance theory explains a broad spectrum of observed surging behaviour in a single framework, and offers an answer to the wider question of why the majority of glaciers do not surge.

scholarly journals Modeling the Biomechanical Influence of Epilaryngeal Stricture on the Vocal Folds: A Low-Dimensional Model of Vocal–Ventricular Fold Coupling

2014 ◽  
Vol 57 (2) ◽  
Author(s):  
Scott R. Moisik ◽  
John H. Esling
Keyword(s):  
Dynamical Behavior ◽  
Model Performance ◽  
Vocal Folds ◽  
Element Model ◽  
Dynamical Response ◽  
Lumped Element ◽  
Glottal Stop ◽  
Lumped Element Model ◽  
Low Dimensional ◽  
Ventricular Folds

Purpose Physiological and phonetic studies suggest that, at moderate levels of epilaryngeal stricture, the ventricular folds impinge upon the vocal folds and influence their dynamical behavior, which is thought to be responsible for constricted laryngeal sounds. In this work, the authors examine this hypothesis through biomechanical modeling. Method The dynamical response of a low-dimensional, lumped-element model of the vocal folds under the influence of vocal–ventricular fold coupling was evaluated. The model was assessed for F0 and cover-mass phase difference. Case studies of simulations of different constricted phonation types and of glottal stop illustrate various additional aspects of model performance. Results Simulated vocal–ventricular fold coupling lowers F0 and perturbs the mucosal wave. It also appears to reinforce irregular patterns of oscillation, and it can enhance laryngeal closure in glottal stop production. Conclusion The effects of simulated vocal–ventricular fold coupling are consistent with sounds, such as creaky voice, harsh voice, and glottal stop, that have been observed to involve epilaryngeal stricture and apparent contact between the vocal folds and ventricular folds. This supports the view that vocal–ventricular fold coupling is important in the vibratory dynamics of such sounds and, furthermore, suggests that these sounds may intrinsically require epilaryngeal stricture.

Evaluation of the Equivalent Lumped Element Parameters of Modified Microstrip Ring Resonator

2015 ◽  
Vol 735 ◽  
pp. 278-281
Author(s):  
Yi Lung Then ◽  
Kok Yeow You ◽  
Mohamad Ngasri Dimon ◽  
Wei Ying Lai
Keyword(s):  
Magnetic Field ◽  
Free Space ◽  
Ring Resonator ◽  
Element Model ◽  
Network Analyzer ◽  
Simulation Data ◽  
Lumped Element ◽  
Lumped Element Model ◽  
Microstrip Ring ◽  
Microstrip Ring Resonator

Microstrip ring resonator (MRR) sensor was modeled by simple equivalent lumped element circuits in free space based on simulation data obtained from Microwave Office (AWR) simulator and comparison was made with the measurements using the E5071C Network Analyzer. The calculated reflection coefficient, |G| and complex input impedanceZinusing lumped element model were compared with the measurements results. Both results showed well agreement with a little discrepancy, basically due to imperfect soldering. The MRR was designed to have operating frequencies between 0.5 GHz and 4.5 GHz. The maximum surrounding of magnetic field,Hϕis within 15 A/m in free space.

scholarly journals A High Q-Factor Outer-Frame-Anchor Gyroscope Operating at First Resonant Mode

Micromachines ◽  
2020 ◽  
Vol 11 (12) ◽  
pp. 1071
Author(s):  
Bo Jiang ◽  
Yan Su ◽  
Guowen Liu ◽  
Lemin Zhang ◽  
Fumin Liu
Keyword(s):  
High Performance ◽  
Microelectromechanical Systems ◽  
Resonant Mode ◽  
Low Noise ◽  
Silicon On Insulator ◽  
Q Factor ◽  
Wafer Level ◽  
High Q ◽  
Ring Structures ◽  
Static Performance

Disc gyroscope manufactured through microelectromechanical systems (MEMS) fabrication processes becomes one of the most critical solutions for achieving high performance. Some reported novel disc constructions acquire good performance in bias instability, scale factor nonlinearity, etc. However, antivibration characteristics are also important for the devices, especially in engineering applications. For multi-ring structures with central anchors, the out-of-plane motions are in the first few modes, easily excited within the vibration environment. The paper presents a multi-ring gyro with good dynamic characteristics, operating at the first resonant mode. The design helps obtain better static performance and antivibration characteristics with anchor points outside of the multi-ring resonator. According to harmonic experiments, the nearest interference mode is located at 30,311 Hz, whose frequency difference is 72.8% far away from working modes. The structures were fabricated with silicon on insulator (SOI) processes and wafer-level vacuum packaging, where the asymmetry is 780 ppm as the frequency splits. The gyro also obtains a high Q-factor. The measured value at 0.15 Pa was 162 k, which makes the structure have sizeable mechanical sensitivity and low noise.

scholarly journals An all-Optical Photoacoustic Sensor for the Detection of Trace Gas

Sensors ◽  
2020 ◽  
Vol 20 (14) ◽  
pp. 3967
Author(s):  
Thomas Lauwers ◽  
Alain Glière ◽  
Skandar Basrour
Keyword(s):  
High Sensitivity ◽  
Element Model ◽  
Remote Detection ◽  
Trace Gas ◽  
Lumped Element ◽  
Highly Sensitive ◽  
Fabry Perot ◽  
All Optical ◽  
Lumped Element Model ◽  
Acoustic Sensitivity

A highly sensitive Fabry–Perot based transduction method is proposed as an all-optical alternative for the detection of trace gas by the photoacoustic spectroscopy technique. A lumped element model is firstly devised to help design the whole system and is successfully compared to finite element method simulations. The fabricated Fabry–Perot microphone consists in a hinged cantilever based diaphragm, processed by laser cutting, and directly assembled at the tip of an optical fiber. We find a high acoustic sensitivity of 630 mV/Pa and a state-of-the-art noise equivalent pressure, as low as ~   2   μ Pa / Hz at resonance. For photoacoustic trace gas detection, the Fabry–Perot microphone is further embedded in a cylindrical multipass cell and shows an ultimate detection limit of 15 ppb of NO in nitrogen. The proposed optical trace gas sensor offers the advantages of high sensitivity and easy assembling, as well as the possibility of remote detection.

Modeling and Optimizing Industrial Inkjet Printhead for Printable Electronics Fabrication

2015 ◽  
Vol 748 ◽  
pp. 15-19
Author(s):  
Lian Bo Ma ◽  
Mao Wei He ◽  
Kun Yuan Hu ◽  
Yun Long Zhu
Keyword(s):  
Experimental Studies ◽  
Element Model ◽  
Printable Electronics ◽  
Lumped Element ◽  
Drop On Demand ◽  
Printing Quality ◽  
Lumped Element Model ◽  
Driving Waveform ◽  
Nonlinear Behaviors ◽  
Inkjet Printhead

The most significant issues in printable electronics fabrication are the printing quality and efficiency delivered by drop-on-demand (DOD) industrial inkjet printhead. Aiming to characterize the nonlinear behaviors of piezoelectric inkjet printhead, the dynamic lumped element model (DLEM) is proposed to cast the original LEM into a time-varying and nonlinear fashion. At the same time , the PSO-based optimization for paramenters is incorporated in DLEM. Due to new characteristics, DLEM can accurately simulate the inkjet-printed nanosilver droplet formation process and effectively predicate optimal combinations of high-frequency driving waveform with high printing quality. From extensive experimental studies, the effectiveness and efficiency of the proposed DLEM is validated.

Thermoacoustically controlled Helmholtz resonators

2013 ◽  
Vol 227 (11) ◽  
pp. 2563-2568
Author(s):  
Konstantin I Matveev
Keyword(s):  
Power Systems ◽  
Thermal Stratification ◽  
Sound Absorption ◽  
Element Model ◽  
Temperature Gradients ◽  
Acoustic Oscillations ◽  
Helmholtz Resonators ◽  
Lumped Element ◽  
Effects Of Temperature ◽  
Lumped Element Model

Helmholtz resonators and their modifications are commonly applied for suppressing unwanted sound, including acoustic oscillations in chambers of propulsion and power systems. Sound absorption characteristics of Helmholtz resonators can be enhanced and controlled with a use of thermal stratification in porous insets inside resonators. A simplified lumped-element model for thermoacoustically augmented Helmholtz resonators is developed in this article. Sample calculations illustrate effects of temperature gradients, porosity, positions of porous insets, and locations of resonators inside chambers.

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