Cascaded piezoelectric composite underwater acoustic transducers with balanced transmitting and receiving performance

To balance transmitting capability and receiving sensitivity in planar underwater acoustic transducers, this work proposes a cascaded piezoelectric composite transducer with a centrally retained PZT ceramic interlayer and a flexible polymer filler. An equivalent parameter model is established and verified by finite element simulations to guide structural optimization. Based on the optimized design, conventional 1–3, epoxy-filled rigid cascaded, and silicone-rubber-filled cascaded transducers are fabricated and evaluated through electrical resonance and underwater acoustic measurements. The silicone-rubber-filled cascaded composite achieves a high thickness electromechanical coupling factor of 0.69. The corresponding transducers maintain a high transmitting voltage response (TVR) of approximately 175 dB and a receiving voltage sensitivity (RVS) of approximately −183 dB. Compared with the conventional 1–3 transducer with the same structural parameters and a PZT volume fraction of 60%, the PZT-5A/silicone-rubber cascaded transducer achieves an RVS improvement of 10.2 dB with a TVR reduction of only 2.9 dB, corresponding to an RVS-gain/TVR-loss ratio of approximately 3.5. In addition, the cascaded transducers broaden the −3 dB bandwidth up to 60.0 kHz. These results demonstrate that the synergy between rigid ceramic support and flexible polymer decoupling provides an effective strategy for improving transmit–receive balance in compact underwater acoustic transducers.