Acoustic sensor with High-Q filter using Helmholtz resonators.

Abstract

This paper reports the development of an acoustic sensor using a Helmholtz resonator (HR) array and a Micro Electro Mechanical Systems (MEMS) piezoresistive cantilever-type differential pressure (DP) sensor element. We designed several arrays with different resonant frequencies (RFs), which are similar to the mechanical RF of the cantilever. Acoustic waves that pass through the HR array are amplified around the RF, thus, the DP sensor responds with high sensitivity around the RF. In the experimental result, all devices with the HR responded to the acoustic waves with approximately 4 times higher sensitivity than the device without the HR at the RF of each HR.