Performance of a high dielectric constant piezoelectric ceramic for ultrasound transducers

A high dielectric material suitable for medical imaging arrays has been investigated. Resonance techniques were used to characterize the complete set of electromechanical properties. Compared to Navy Type VI material a two-fold increase in clamped permittivity was observed (epsilon(33)(S)/epsilon(0) of 2730 vs 1470), while the coupling coefficient for linear array elements was almost identical (k(33)' of 0.68 vs 0.69 for Navy Type VI). Measurements indicated high coupling and permittivity at frequencies up to at least 60 MHz. Models for 1-3 composites incorporating this material revealed an effective thickness coupling of 0.68 at a 55% volume fraction of ceramic. Simulated device performance indicated a 4dB sensitivity increase for array elements incorporating this material when compared to conventional materials.