Novel materials and fabrication technology for medical ultrasonic transducers

Ultrasonic imaging in the frequency range from a few MHz to beyond 20 MHz has been used for diagnosis of many diseases. Ultrasound at frequencies higher than 20 MHz has applications in dermatology, ophthalmology and intravascular imaging. The performance of ultrasonic imaging systems especially at high frequencies depends critically upon the transducers/arrays, the design of which in turn is determined to a large degree by the materials and fabrication methodology of the piezoelectric element and supporting structures. Recent developments in these areas are discussed in this paper.