The Research Of The Low Frequency Three-dimensional MEMS Vector Hydrophone

The trend of development of vector hydrophone turns to low frequency, little size, high SNR for the demand of faraway detective and low frequency measurement. The MEMS vector hydrophone is a new solution of achieving high capability with small size.Basing on the demand of designing the vector hydrophone, we have designed the sense organ and external circuit of the capacitance acceleration sensor in the article, and four different types of vector hydrophone have been made and measured. The result of measurement shows that with high sensitivity(909mV/g) the self-noise of the vector hydrophone decrease obviously, which can satisfy the design request.We made six 3-D capsule vector hydrophones using the capacitance acceleration sensor in this article, the size of which isφ28×48mm, and the vector hydrophones have been measured in the standing wave pipe. The result of measurement shows the pressure sensitivity of 1#, 6# vector hydrophone is not less than -196.4dB,-200.1dB(0dB=1V/μPa,500Hz)separately, and the average pressure sensitivity (0-400Hz)of 2# vector hydrophone is -199.2dB(400), and the average pressure sensitivity (0-800Hz)of 12# vector hydrophone is -192.7dB(800),and sensitivity of pressure channel is -201dB(0dB=1V/μPa, 500Hz).The research shows that the MEMS vector hydrophone has following advantages: small size, low frequency, light weight, better directivity in work band, high SNR and so on.