Research On Broadband And Highly Sensitive Underwater Acoustic Transduce

To improve the detection performance of sonar systems,this paper develops a broadband highly sensitive hydroacoustic transducer with a "pyramidal" structure from two aspects: extending the bandwidth of the transducer and improving its sensitivity.In the research of highly sensitive piezoelectric materials,the "BPM" and "MPM" piezoelectric materials have been proposed by improving the type 1-3 piezoelectric composites.The "BPM" piezoelectric material consists of a piezoelectric ceramic base,an array of piezoelectric ceramic pillars and a metal cover plate,while the "MPM" piezoelectric material consists of a lower metal cover plate,an array of piezoelectric ceramic pillars and an upper metal cover plate.The frequency equation of the sensitive element is solved by the electromechanical equivalence diagram,and the resonant frequency variation with geometry is obtained.At the same time,the finite element simulation software is applied to simulate the above two piezoelectric materials and obtain the preferred range of material dimensions.In order to select one of the "BPM" type piezoelectric materials and "MPM" type piezoelectric materials for the development of a pyramidal structure of hydroacoustic transducers,two types of highly sensitive piezoelectric sensitive elements were prepared,and the two types of highly sensitive piezoelectric sensitive elements were used to The "BPM" type single layer sensitive element transducer and the "MPM" type single layer sensitive element transducer were fabricated.Taking into account the electro-acoustic properties of the two transducers and the ease of preparation of the sensitive elements,the "BPM" type piezoelectric material was selected as the active material for the broadband high-sensitivity transducer.Based on the above research,a "pyramid" type transducer sensitive element structure was designed based on the multimode coupling theory,effectively expanding the bandwidth of the transducer.By establishing the transducer fabrication process,a prototype broadband high-sensitivity transducer has been developed.The performance of the developed "pyramid" structure broadband highly sensitive hydroacoustic transducer was tested and the following results were obtained: transmit voltage response of 182.9d B(bandwidth of 170 k Hz),receive sensitivity of up to-173.7d B(bandwidth of 110 k Hz),-6d B horizontal beam opening angle of 8.1 °.All performance indicators have been significantly improved compared to the 1-3 piezoelectric composites,achieving the desired goal of broadband high sensitivity.