A conventional spherical acoustic lens is modified by restricting its aperture in the form of a slit to provide directional sensitivity. The spacing between the two parallel absorbing sheets forming the slit is adjustable ...

The successful fabrication of ultrasonic immersion transducers is reported. Transducers are observed to operate from 1 MHz to 20 MHz in water, with the frequency range limited by electronics, not the transducers. Transmission ...

The current state of a novel technology, surface microfabricated ultrasonic transducers, is reported. Experiments demonstrating both air and water transmission are presented. Air-coupled longitudinal wave transmission through ...

Phase aberration correction based on time delay estimation via minimization of sum of absolute difference (SAD) between radio frequency (RF) signals of neighboring elements is studied in the presence of missing elements. ...