Advances in MEMS Hydrophone Technology

MEMS (Micro-Electro-Mechanical System) hydrophone, with the advantages of low cost, low power consumption, and miniaturization, has rapid development and wide application in acoustic detection. The complexity of the marine environment and the development of underwater equipment have proposed higher requirements for the performance of MEMS hydrophones. However, the sensor performance of MEMS hydrophones is affected by multiple factors, such as structure, principle, and MEMS processing technology. Many novel MEMS hydrophones with new principles, new structures, and new materials have been established to improve the sensitivity and bandwidth of MEMS hydrophones. In this study, MEMS hydrophones are divided into optical MEMS hydrophones, electrical MEMS hydrophones, and thermal MEMS hydrophones according to the principle used. Additionally, the basic working principles of different MEMS hydrophones are summarized, and the characteristics of MEMS hydrophones with different principles are analyzed. Furthermore, the advantages and disadvantages of different materials and structures are compared regarding the tested performance parameters. The contribution of this study lies in systematically reviewing the development process of three types of MEMS hydrophones, especially the development and improvement of piezoresistive, hot-wire, and interferometric MEMS hydrophones, involving the research hotspots and latest progress. Finally, the characteristics of MEMS hydrophone development are demonstrated, the existing problems are discussed, and the future development trend is prospected.