Model measurement of the microphone array

Abstract

The use of silicon has allowed the fabrication of microphones with integrated electronic circuitry and the development of the FET microphone. The introduction of lithographic technique has resulted in microphones with very small (1 mm2) diaphragms with specially shaped backplates. The application of corrugated diaphragms ensures promising future development of silicon microphones. On the basis of this work the arrangement can be prepared for an encapsulation of a miniature microphone chip. Frequency response of the microphone arrays of various types was measured on models in an enlarged scale. It was proven by the numerical results and by the measurements on the model that this manner of encapsulation is possible and advantageous. It was concluded that there is a satisfactory agreement between the analytical description and experimental results of model measurements. The measurement can be transposed to frequency ranges in the ratio of wavelength and dimensions and the damping of modes can be calculated. This problem solution is cheaper than measurement of the miniature microphone chip [Z. Kvor, ‘‘Study of the Air-gap and the Influence of the Microphone Position on the Substrate Plate,’’ Report Copernicus CP 940515 (1997), P. R. Scheeper, Sensors and Actuators A44, 1–11 (1994)].