THEORETICAL-MODELS TO DESCRIBE THE COUPLI NG BETWEEN VIBRATING MEMBRANES AND THIN GAS LAYERS

Theoretical models to describe the behaviour of membranes or plates lo aded by gas films have recently been developed (Bruneau, 1993, 1994). The conventional models (Skvor, 1991) used to describe the behaviour o f electrostatic or piezoelectric microphones or loudspeakers are impro ved in that several effects usually neglected al-e taken into account in order to obtain the accurate models that are required by the curren t level of miniaturization and by new devices and applications, especi ally in the high-frequency range (up to 100 kHz and more). The aim of this paper is to present and compare the results obtained from the dif ferent models.