Design of a 50 MHz annular array using fine-grain lead titanate

Abstract

An annular array with equal area elements has been fabricated and tested. The elements are made from a novel fine-grain lead titanate which was micromachined using a laser to form the kerfs. Resonance methods showed the lead titanate exhibited electromechanical properties similar to bulk materials, including a thickness coupling k/sub t/ of 0.49 and low permittivity (/spl epsiv//sub 33//sup S///spl epsiv//sub 0/=178). An average center frequency of 53 MHz with 40% bandwidth was obtained across all the elements. Crosstalk levels were below -20 dB in water. Good agreement was obtained between the measured results and a finite element model.