Ultrasound characteristics of focused axisymmetrically curved surface transducers

A high-speed method for exactly calculating the time-dependent pressure of the radiated acoustic field from pulse-excited axisymmetrically curved surface or lens transducers using the Rayleigh surface integral is presented. The time-dependent pressure of a medical lens transducer with its outer surface shaped like a revolving arc is calculated as an example. Convolution-algorithm procedures are used to study the acoustic radiation field for various forms of exciting pulses. In the calculations, an integral representation of the impulse response function is reduced to a one-dimensional integration. With the help of the triangle criterion for identification and the principle of one-dimensional constriction, the calculation can be scanned over the segmented ranges of integration to carry out the numerical analysis. Ultrasound characteristics of the transducers are calculated, and their relationship to the structure of the transducers is examined.