Abstract. A 16-by-16 element array is operated at a center frequency of 2.25 MHz using a 256-channel transmitter system. Reception is performed with a subset of elements of the array or with a separate single element probe. The beam fields generated in water have been simulated and compared to experiments with excellent agreement. 3D imaging of defects inside components has been addressed only by electronic steering and focusing to various depths of the inspected component. Work has also been done using an 8-by-8 element array