Steering of limited diffraction beams with a two-dimensional array transducer

The production and steering of limited diffraction beams with a two-dimensional array are studied. Results show that good limited diffraction beams can be produced if the size of the array elements is small and the array aperture is compensated so that the projection of the aperture on a plane perpendicular to the beam axis is a constant annular ring pattern. The electronic system for controlling the two-dimensional array is described, and methods to simplify it are proposed