A two-dimensional hydrophone array using piezoelectric PVDF

A new development in ultrasound measurement technology-a two-dimensional hydrophone array-is presented. Using the established technology of PVDF ultrasound sensors, this novel hydrophone array has 64 circular elements (each of 0.2 mm diameter) arranged in an 8/spl times/8 pattern with 1 mm spacing between element centers. Construction of the hydrophone array is discussed, and results of a series of measurements to characterize its performance are presented. Hydrophone elements exhibit a flat frequency response (/spl plusmn/0.8 dB over the frequency range 1-25 MHz) and have an effective radius that appears to have minimal frequency dependency (within /spl plusmn/8% of mean value) and is within 8% of the nominal sensor radius. The hydrophone array performance also is assessed in terms of dynamic range, interelement variation, and acquisition time. Applications of this new technology (such as mapping of transducer fields, assessment of diagnostic ultrasound fields, and use in point source-array receiver nondestructive testing) are discussed.