Author(s): Abramova Karina, Honzík Petr, Joly Nicolas, Durand Stéphane, Bruneau Michel
Electroacoustic MEMS transducers are involved in a variety of applications such as consumer devices, but their use increases today also in the domain of wireless noise monitoring systems. Since the high quality (and low price in case of high number of sensor nodes) is needed, the precise modelling of such devices leading to the new solutions is of interest. The transducer, whose model is described herein, consists of a square plate as a moving electrode loaded by a thin fluid gap and a rectangular peripheral cavity, the square shape of the transducer being advantageous from the point of view of microfabrication because of its geometrical simplicity. The analytical approach relies on the integral formulation for the acoustic pressure field in the thin fluid gap (the dissipative effects of the thermal and viscous boundary layers being taken into account) coupled with the displacement field of the plate expressed as a sum of eigenmodes. Special attention is paid herein to the expression of the eigenfunctions of the plate, which are searched for in an approximated analytical form of two-dimensional Fourier series, the coefficients of the series being derived from a simple numerical solution for the plate without the loading acoustic elements. The acoustic pressure sensitivity of the transducer, used as an acoustic receiver, is obtained from the analytical model of the transducer, the comparison with the numerical results provided by a finite element model (a reference against which the analytical results are tested) is presented and discussed.
Name: Dr Petr Honzík
Country: Czech Republic