High-power, high-frequency, broad constant beamwidth 1-3 composite transducer

Abstract

A difficult transducer design is to produce broad beamwidths with high power at high frequencies. Transducers formed on a cylindrical arc can produce broad beamwidths with greater power than conventional planar transducers with the same beamwidths because of their larger area. These transducers also have the added benefit of directivity patterns, with constant beamwidth as a function of frequency, instead of the typical decreasing beamwidth as with conventional planar transducers. The utilization of 1-3 PZT composite piezoelectric material enhances the performance and simplifies construction of constant beamwidth transducers due to its ability to be easily formed into a cylindrical arc using a single piece of material several wavelengths in dimension. Test results show that a 1-3 composite constant beamwidth transducer provides almost a 10 dB higher source level than a comparable 1-3 composite planar transducer. The constant beamwidth transducer also produces a 70° constant beamwidth directivity pattern from 75 to 300 kHz. This device is being used as a broad bandwidth standard transducer because of its stable pattern characteristics.