An Ear-Inspired Sound Pressure Amplification Structure for Fabry-Perot Acoustic Sensor

In this paper, inspired by the ossicular chain in human middle ear, a miniature sound pressure amplification structure (SPAS) based on double $10\ \mu \mathrm{m}$-thickness E-shaped steel diaphragms with the corresponding diameters of 15 mm and 3 mm was developed to enhance the sensitivity of diaphragm-type Fabry-Perot (F-P) acoustic sensor. FEM simulation demonstrated the availability of the SPAS in terms of the achieved acoustic field response within a certain frequency range. Then acoustic test showed that the F-P acoustic sensor using a silver diaphragm, adapted with the developed SPAS, achieved a remarkable sensitivity amplification ratio of up to ∼7.6 in the range of 1.5∼2.1 kHz, which can be further widened by optimizing structure dimensions and membrane materials.