Electrostrictive transducers for medical ultrasonic applications

Ultrasonic phased or sector array transducers were built using PMN-PT based electrostrictive materials. Large field-induced piezoelectric coefficients were obtained in these relaxor-type materials at relatively low DC bias (K_t=0.43-0.50 at 5 KV/cm). The electrostrictive transducers have similar sensitivity and bandwidth compared to conventional PZT transducers. By choosing the appropriate composition and process, the sensitivity variation of electrostrictive transducers can be minimized to within 3 dB over the operating temperature range. The clinical results demonstrate the benefit of using electrostrictive materials to obtain elevation aperture control