Study on miniaturization of low-frequency, co-vibrating vector hydrohones based on piezoelectric accelerometers

Summary form only given. According to the acoustic theory and the working principle of piezoelectric accelerometers, a vector hydrophone of co-vibrating type is proposed from three-axis piezoelectric accelerometers with vibration-type vector hydrophones. To miniaturize low-frequency vector hydrophones, a kind of three-axis piezoelectric accelerometers with high sensitivity and small sizes was designed, whose output is electric charge with the sensitivity of each channel up to 11000 pC/g. Moreover, the accelerometer is without internal ICP conversion circuit. On this basis, a spherical vector hydrophone with three velocity channels and one channel of sound pressure has been developed. The diameter of the vector hydrophone is 130 mm, the frequency band is of 20-1000 Hz, the velocity-channel sound pressure sensitivity is of -178 dB (1000 Hz, 0 dB=1 V/¿Pa)and the channel sound pressure sensitivity is of -211 dB. Results show that the diameter of the spherical vector hydrophone operating at electric charge output mode can be reduced from 220 mm to 130 mm without lowering the work standards of vector hydrophones.