ON THE PRESSURE FIELD OF A TRANSDUCER IN THE FORM OF A CURVED STRIP

A new analytical expression for the impulse response of a transducer in the form of a curved strip is derived. The radiator is defined as part of a concave spherical shell delimited by two horizontal parallel planes and two vertical parallel planes. The field of the transducer is obtained by means of the impulse response method proposed by F. Oberhettinger [J. Res. Natl. Bur. Stand. 65, 1-6 (1961)] and P. R. Stepanishen [J. Acoust. Sec. Am. 49, 841-849 (1971)] and the formalism developed by M. Arditti et al. [Ultrason. Imag. 3, 37-61 (1981)]. Exact analytical expressions of the impulse response and of the continuous pressure field were obtained in the three planes xOy, xOz, yOz, where Oz is the propagating axis of the ultrasound and O the focal point. The results of numerical modeling were compared with experimental results obtained using a 5-MHz rectangular spherical strip (7X21 mm) focused at 75 mm. The agreement was excellent.