A universal analysis method for an omnidirectional broadband spherical transducer based on 1-3-2 piezoelectric composite

Piezoelectric composites, consisting of piezoceramic and polymer materials, can reduce the brittleness and strength of ceramics and offer an innovative approach to improving the performance of ultrasonic transducers. Recent advances in piezoelectric composites have proposed a variety of transducers with different connectivity types, while spherical transducers composed of 1-3-2 piezoelectric composites have not yet been investigated. Here, we propose a 1-3-2 piezoelectric composite spherical transducer (1-3-2-PCST) capable of achieving broadband and omnidirectional radiation in breathing mode. The proposed design is composed of six identical spherically curved square piezoelectric composites. A universal analysis method for the 1-3-2-PCST based on the electromechanical equivalent circuit is derived. The effects of geometric dimensions and volume fraction of piezoceramic on the effective electromechanical coupling coefficient and resonance/anti-resonance frequency are investigated. Experiments and the finite element method validate the correctness of the universal analysis method. Our design bridges the gap between the spherical transducer and 1-3-2 piezoelectric composite and may have far-reaching implications for hydrophones, medical diagnosis, and ocean exploration.