Toroidal and conical piezoelectric polymer transducers for long range focusing.

Abstract
Ultrasound focusing transducers with a conical or a toroidal radiating surface are studied theoretically and experimentally, and it is shown that these non-spherical transducers have high capability in converging the sound beam over a long range along the axis. The axial and lateral field distributions are calculated for toroidal transducers as well as for conical transducers, and the focusing properties are evaluated for various aperture geometries. To facilitate the transducer fabrication, quasi-toroidal transducers are proposed, which are composed of a few conical or several cylindrical segments. Experimental examinations using flexible piezoelectric polymer sheets show that the conical and quasi-toroidal transducers of 1-inch diameter operating at a frequency of 3.6 MH2 produce the sound beam with the full-width at half-maximum of6to10wavelengths in the range of70mm to 220 mm.

This publication has 0 references indexed in Scilit: