Hydrothermal PZT thick film ultrasonic transducer for 2 to 40 MHz frequency band

High frequency, wide band characteristic and high intensity ultrasonic transducer was fabricated by hydrothermal deposition technique of lead zirconate titanate (PZT) polycrystalline thick film. The transducer had a 20-mu m-thick PZT layer on a 40-mu m-thick titanium substrate in an active area of 1.5 mm x 8 mm. The mechanical resonance frequency was approximated by the phase velocity of the dilatational wave of Ti substrate and the hydrothermal PZT thick film. The half wavelength resonance frequency of the vibration plate of the Ti substrate and the hydrothermal PZT thick film was about 40 MHz. This ultrasonic transducer radiated ultrasounds in the frequency range from 2 to 40 MHz within a 6 dB deviation using thickness vibration mode. This is first report of the ultrasonic transducer using the hydrothermal PZT thick film at over 20 MHz operation characteristics.