A low-frequency broadband ring transducer driven by the flextensional structure.

The flextensional transducer (FT) is a typical low-frequency transmitting transducer that is capable of high-power operation due to its capacity for displacement amplification. This article uses the structural configuration of the class IV FT as the basis for designing a ring transducer, which is a circular structure comprising a multitude of class IV flextensional structures as well as circular acoustic radiation structures. The flextensional structure drives the circular acoustic radiation structure, which in turn generates sound waves at low frequencies. It concurrently enhances the intensity of the sound source. Moreover, the acoustic radiation structure is designed to operate with two resonances that can be coupled with each other to extend the bandwidth of the transducer. A finite element model of the low-frequency broadband ring transducer was developed, and its structural parameters were optimized to achieve the optimal bandwidth. The optimization of the transducer was followed by the fabrication of its prototype, which was then used to evaluate its underwater acoustic performance. The results of measurements showed that the proposed transducer could successfully couple two modes of vibrations to yield an in-band fluctuation of approximately 12 dB in the range of frequencies of 540 to 1580 Hz.