Capacitive micromachined acoustic transducer

Abstract

A micromachined capacitive acoustic transducer including an electrode formed by a perforated plate and another electrode formed by a shallowly corrugated membrane anchored at one or more positions on the substrate which also supports the said perforated plate is described. Also disclosed includes: a fixed perforated plate; a movable shallowly corrugated membrane having holes to form acoustic filter to a certain frequency or a range of frequencies spaced from the perforated plate that is anchored in one or more location but loose at other locations; a support structure in the perforated plate maintaining the minimum separation between the membrane and the perforated plate near the perimeter.

1 . A micromachined miniature acoustic transducer including 
 a capacitor formed by a perforated plate and a membrane;    a perforated plate having well defined perforation holes that serves as one electrode of the said capacitor;    a shallowly corrugated membrane that is anchored at one or more locations to form another electrode of the said capacitor. The length of corrugation for the said membrane is predetermined based on the desired sensitivity requirement;    a substrate on which the said membrane and the said perforated plate are anchored; and    the said membrane having an anchoring structure that forms a tuning fork with the said perforated plate.