Alves Fabio, Park Jaehyun, McCarty Leland, Rabelo Renato, Karunasiri Gamani
Naval Postgraduate School, Monterey, CA 93943, USA.
Sensors (Basel). 2022 Feb 10;22(4):1337. doi: 10.3390/s22041337.
A MEMS directional acoustic sensor housed in an air cavity and operated underwater in a near-neutral buoyancy configuration is demonstrated. The sensor consists of two wings connected by a bridge and attached to a substrate by two centrally mounted torsional legs. The frequency response showed two resonant peaks corresponding to a rocking mode (wings moving in opposite directions) and a bending mode (wings moving in the same direction). Initial tests of the sensor using a shaker table showed that the response is highly dependent on the vibration direction. In air, the sensor showed a maximum sensitivity of about 95 mV/Pa with a cosine directional response. Underwater, the maximum sensitivity was about 37 mV/Pa with a similar cosine directional response. The measured maximum SNR was about 38 dB for a signal generated by a sound stimulus of 1 Pa when the sensor is operated near the bending resonance. The results indicate that this type of MEMS sensor can be operated in a near-neutral buoyant configuration and achieve a good directional response.
展示了一种微机电系统（MEMS）定向声学传感器，它封装在空气腔中，并以近中性浮力配置在水下运行。该传感器由通过桥连接的两个翼片组成，并通过两个位于中心的扭转腿连接到基板上。频率响应显示出两个共振峰，分别对应于摇摆模式（翼片向相反方向移动）和弯曲模式（翼片向相同方向移动）。使用振动台对传感器进行的初步测试表明，响应高度依赖于振动方向。在空气中，该传感器显示出约95 mV/Pa的最大灵敏度，具有余弦方向响应。在水下，最大灵敏度约为37 mV/Pa，具有类似的余弦方向响应。当传感器在弯曲共振附近运行时，对于1 Pa的声音刺激产生的信号，测得的最大信噪比约为38 dB。结果表明，这种类型的MEMS传感器可以以近中性浮力配置运行，并实现良好的方向响应。
