Performance of 50 MHz transducers incorporating fiber composite, PVDF, PbTiO₃ and LiNbO₃

The performance of high frequency single element transducers depends greatly upon the mechanical and electrical properties of the piezoelectric materials used. This study compares the design and performance of transducers incorporating different materials. The materials selected include 1-3 PZT fiber composite, PbTiO₃ ceramic, PVDF film, and LiNbO₃ single crystal. Transducers were tested for insertion loss and -6dB bandwidth using the pulse/echo response from a flat quartz target. All transducers were constructed with a 3 mm aperture size and f number between 2 to 3. Backing and matching materials were varied to optimize each design. An additional design consideration is electrical impedance matching to 50 ohm especially for the fiber composite and PbTiO₃ transducers due to their relatively high dielectric constant. Sensitivity between transducers displayed a significant variation, with insertion losses from -21.3 dB to -46 dB. -6dB bandwidths were in the range of 47 to 118%. In-vitro UBM images of human eye were made to compare the different transducers.