Optimum beam steering of linear phased arrays

A model was developed to compute acoustic pressure distribution of the waves radiated from an ultrasonic linear phased array. Based on the model, beam directivity and steerability were studied for various transducer parameters such as number of elements, inter-element spacing, element width, and transducer frequency. Optimal transducer parameters were determined to obtain the best beam directivity by minimizing the main lobe width, eliminating grating lobes, and suppressing side lobes. It was shown that the solutions for the phased arrays can be reasonably approximated by the simple solutions of discrete line sources, if the element width is reasonably smaller than the wavelength or the steering angle is relatively small. The inter-element spacing as well as the number of elements plays an important role in determining transducer performances. (C) 1999 Elsevier Science B.V. All rights reserved.