A method to measure and interpret input impedance of small acoustic components

Rodrigues, Dominique; Guianvarc'H, Cécile; Durocher, Jean-Noël; Bruneau, Michel; Bruneau, Anne‐Marie

doi:10.1016/j.jsv.2008.02.017

Cited by 14 publications

(22 citation statements)

References 7 publications

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“…introducing the membranes vibroacoustic behavior coupled to the acoustic field in the numerical modeling, iii. achieving an experimental validation of the analytical and numerical models of miniature acoustic systems presented here [10].…”

Section: Resultsmentioning

confidence: 91%

New planar nano-gauge detection microphone: Analytical and numerical acoustic modeling

Guianvarc'H

Verdot

Czarny

et al. 2013

The Journal of the Acoustical Society of America

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The miniaturization of microphones is of great interest for several fields, such as medical applications (audio implants), or consumer electronics (cell phones). Almost all existing miniature microphones rely on electrostatic transduction and offer good performances (sensitivity, frequency bandwidth). However, their sensitivity, proportional to the membranes area, would be dramatically reduced in case of extreme miniaturization. A new concept of microphones developed by CEA-LETI, which uses membranes moving in the plane of the substrate and inducing strain on piezoresistive Si nano-gauges (M&NEMS technology), seems promising for its miniaturization potential without significant decrease of sensitivity. The design and optimization of such planar piezo-resistive microphone require a deep understanding of its acoustic and vibroacoustic behavior. Regarding the small dimensions of the slits (1–100µm) and the sharp discontinuities in the microphones structure, viscous and thermal effects in the boundary layers and turbulent perturbations are of great importance, and must then be taken into account with high accuracy in device modeling. The aim of the present work is to provide accurate analytical and numerical (FEM) models able to gather all these effects in a consistent manner, and to suggest an experimental method to check their validity.

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Section: Resultsmentioning

confidence: 91%

New planar nano-gauge detection microphone: Analytical and numerical acoustic modeling

Guianvarc'H

Verdot

Czarny

et al. 2013

The Journal of the Acoustical Society of America

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“…The particle velocity and the temperature variation profiles in the fluid gap are obtained as solutions of the Navier-Stokes equation and Fourier equation for heat conducting respectively under several approximations (see [1,8,9] for details). Introducing the mean values of these profiles into the conservation of mass equation leads to the wave equation for the acoustic pressure in the fluid gap, accounting for the state equation…”

Section: Equations Governing the Pressure Variationsmentioning

confidence: 99%

Miniaturized electrostatic receiver with small-sized backing electrode

Podkovskiy¹,

Honzík²,

Durand³

et al. 2013

The Journal of the Acoustical Society of America

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A miniaturized electrostatic receiver design, having a central cylindrical backing electrode of small radius surrounded by a flat annular cavity behind the circular membrane, can lead to both a higher sensitivity and a larger frequency bandwidth compared to the ones achieved with other designs, while bringing a geometrical simplicity which is advantageous from the point of view of microfabrication. An appropriate computational method, relying on a specific 2-D axisymmetrical simulation using an adaptive mesh and accounting for both viscous and thermal boundary layer effects, provides results against which analytical results can be tested. An analytical approach, which leads to solutions based on the eigenmode expansion of the membrane displacement, the acoustic pressure field depending on the radial coordinate in the central fluid gap but being assumed quasi-uniform in the annular cavity, is much faster in terms of running time and appears to be sufficiently accurate to achieve final optimization of this kind of devices.

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“…Being concerned by the use of this analytical approach when lowuncertainties on the behavior of acoustic fields generated or measured by these transducers are required up to 100 kHz, accurate theoretical results could be obtained provided that the main geometrical parameters, namely here those characterizing the air gapa nd the holes in the backing electrode, be accounted for in am ore realistic manner than in the previous paper [1]. Note that, beyond the numerical approaches [3,4], an appropriate analytical modeling to estimate accurately the displacement field and the frequencyresponse of transducers (including MEMS devices and non standard conditions)would be of interest when dealing with, among others, the acoustic centre and/or the free-field correction of condenser microphones [5,6,7], the measurements in couplers [8], or the free-field calibration in the highest frequencyr ange (upt o1 00 kHz for measuring for example shockwaves profiles [9]). …”

Section: Introductionmentioning

confidence: 99%

Analytical Modeling of Electrostatic Transducers in Gases: Behavior of Their Membrane and Sensitivity

Lavergne¹,

Durand²,

Joly³

et al. 2014

Acta Acustica united with Acustica

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Electrostatic transducers have been appropriately characterized during the last decades for their common use under standard conditions. But nowadays, their miniaturization (using MEMS processes)and their uses for metrological purposes under non-standard conditions (i.e. in high frequencyr anges, in gasm ixtures, and at various static pressures and temperatures)r equire am uch deeper characterization with respect to these uses. Though recent literature on this topic [Lavergne et al., J. Acoust. Soc. Am., 128(6),p p. 3459-3477, 2010] leads to satisfying results for electrostatic microphones according to these requirements, the analytical solution givenisnot always sufficiently precise to interpret phenomena and must be improvedt oc haracterize more accurately both the displacement field of the membrane up to high frequencies (100 kHz)and the sensitivity as afunction of the frequency. Thus, the aim of the work presented here is to propose improvements to this analytical procedure for receivers (event ransmitters)w hen coupling between membranes, slots, holes and cavities are involved. These analytical improvements are obtained in introducing amore realistic volume velocity distribution to describe the fluid flowa tt he end of each hole. The improveda nalytical model relates to that presented previously for electrostatic microphones (and is based on it)inorder to compare the last analytical results with both the theoretical ones obtained previously and the experimental ones available.

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A method to measure and interpret input impedance of small acoustic components

Cited by 14 publications

References 7 publications

New planar nano-gauge detection microphone: Analytical and numerical acoustic modeling

New planar nano-gauge detection microphone: Analytical and numerical acoustic modeling

Miniaturized electrostatic receiver with small-sized backing electrode

Analytical Modeling of Electrostatic Transducers in Gases: Behavior of Their Membrane and Sensitivity

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