BEAM STEERING ULTRASONIC TRANSDUCERS STUDY.

This study of applying phased array drive principles to the design and operation of ultrasonic transducers and delay lines indicates the feasibility of employing controlled beam steering in active ultrasonic signal processing devices. The technique has potential applications in devices such as electronically variable delay lines, scanning correlators, doppler processors, time inverters, and radar range simulators. The study included the further development of thin-film transducers, both cadmium sulfide and zinc oxide. Zinc oxide films vacuum-deposited on a cold substrate are shown to produce a substantially higher frequency of operation than cadmium sulfide because they provide superior electromechanical coupling. Six beam steering configurations have been investigated parallel uniform gratings, uniform grating wedge lines, ultrasonic surface wave lines, Rowland circle configurations, and acoustic diffraction spectrometers. The first three approaches were proved to be too inefficient for practical application because of excessive signal loss at angles off transducer boresight. In contrast, the latter three configurations show definite promise that warrants further investigation and development to exploit possible applications of the configurations in signal processing devices and systems. Author