Capability of segmented annular arrays to generate 3-D ultrasonic imaging

Abstract

The main object of this paper is to show the influence of the array geometry on the image properties. This is made by comparing the beam generated by three 2D arrays: a squared array, a regular segmented annular array with a star distribution of elements and a segmented annular array with elements of unitary aspect ratio. The three arrays are equivalent in the sense that their size, number of active elements and active areas are similar and that they emit the same ultrasonic pulse. After analysing theoretically the main beam and grating lobes in the steering case, the paper concludes advising to use segmented annular arrays with elements of unitary aspect ratio as they produce ultrasonic beams with good properties even for an interelement spacing of 1.1λ.