An acoustically transmissive electrochemical vector hydrophone with horn-driven velocity amplification

Low-frequency acoustic sensing is critical for underwater target detection and sound source localization, yet the sensitivity of conventional vector hydrophones is fundamentally limited by the resonance of suspended co-oscillating structures. This paper presents a transmissive electrochemical vector hydrophone with horn-driven particle velocity amplification. By adopting a fixed transmissive configuration, structural resonance is effectively eliminated, while the horn structure enhances particle velocity to improve low-frequency sensitivity. The particle velocity amplification mechanism and its coupling with the electrochemical transduction process are analyzed. Numerical simulations are performed to investigate the effects of horn geometry and structural parameters on the frequency response. Experimental results demonstrate a peak sensitivity of approximately -180 dB re 1 V/μPa at 10 Hz and an effective bandwidth of 10-300 Hz after circuit compensation. The hydrophone exhibits good linearity, a wide dynamic range, and a figure-eight directivity pattern with a null depth exceeding 40 dB, indicating its suitability for low-frequency underwater acoustic detection, with potential applications in underwater surveillance, ocean environmental monitoring, and marine geophysical exploration.