Displacement field of the membrane of condenser microphones at high frequencies: Improvement of analytical solution

Thomas Lavergne (1) , Stéphane Durand (1) , Michel Bruneau (1) , Nicolas Joly (1)

1 LAUM - Laboratoire d'Acoustique de l'Université du Mans

Condenser microphones are reciprocal transducers whose properties (sensitivity, bandwidth and reliability) make them powerful measurement tools. For their common use under standard conditions they have been appropriately characterised for nearly thirty years. But nowadays, their miniaturisation (using MEMS processes) and their new uses for metrological purposes under non-standard conditions (i.e. in high frequency ranges, in gas mixtures, and at various static pressures and temperatures) require a much deeper characterisation with respect to these new uses. Though recent literature on this topic [JASA, 128(6), pages 3459-3477 (2010)] leads to satisfying results according to these new requirements, the analytical solution given is not always sufficiently precise to interpret phenomena and must be improved to characterise more accurately the displacement field of the membrane up to high frequencies (up to 100 kHz). Thus, the aim of the work presented here is to propose an improved analytical solution (especially by taking into account more appropriately the finite surface corresponding to the holes in the backing electrode) and to deduce results of interest, in particular concerning metrology purposes.

Mots clés: Condenser microphone; Reciprocal transducer; Laser scanning vibrometer; Analytical solution

Domaines: Acoustique [physics.class-ph]

Thomas Lavergne, Stéphane Durand, Michel Bruneau, Nicolas Joly. Displacement field of the membrane of condenser microphones at high frequencies: Improvement of analytical solution. Acoustics 2012, Apr 2012, Nantes, France. ⟨hal-00810932⟩