Structural design of an acoustic planar array transducer by using the equivalent circuit method

Underwater acoustic transducers are used to detect and track targets by using sound waves in underwater environments. To enhance the performance, they can be arranged in various formations to create arrays. However, acoustic interaction between the constituent channels of array transducers is inevitable, and it distorts their characteristics. In this study, the transmitting voltage response (TVR) spectrum of an acoustic planar array transducer is analyzed by considering the crosstalk between channels. The transmitting performance of an array transducer is frequently analyzed using the conventional finite element method (FEM). However, when the size of the array is large, the time and cost of computation using the FEM increase to almost prohibitive levels. To overcome this problem, a new equivalent circuit method (ECM) is developed to analyze the acoustic characteristics of an underwater array transducer. The ECM is validated by comparing its TVR spectrum with that analyzed using the FEM. After validation, the ECM is utilized to design the optimal structure of a planar array transducer having the broadest bandwidth. The sample analysis conducted using the ECM was approximately 1780 times faster than that by the FEM. Therefore the ECM developed in this work can facilitate the design of an underwater planar array transducer with a superior speed and efficiency compared with those achievable with the conventional numerical analysis methods such as the FEM.