DC-biased electrostrictive materials and transducers for medical imaging

The field-induced electromechanical properties of several electrostrictive materials have been studied for ultrasonic transducer applications. This paper reviews the most important material properties and summarizes the advantages of using electrostrictive materials in medical imaging applications. By controlling electrostrictive material properties, transducers can be operated over a broad temperature range with minimum variation of sensitivity (within 3dB over the operating temperature range). Electrostrictive transducers with either 2 or 4 elevation aperture groups have been built and the results demonstrate the benefits of using electrostrictive tuning capability to achieve elevation aperture control and apodization. A novel type of f₀/2f₀ switchable transducer in which the operating frequency can be switched between two separated frequency bands expands the usable frequency range to over 100% -6dB bandwidth