In the paper, the effects of transducer parameters on the beam directivity and pressure in the steering direction were studied, which include number of elements, inter-element spacing, element size, steering angle and aperture length. The criteria considered are (1) minimization of main lobe width, (2) elimination of grating lobes, (3) suppression of side lobes, and (4) maximization of pressure in the steering direction. The first objective is fulfilled by increasing N and/or d, whereas the second objective can be achieved by limiting the inter-element spacing below its critical value. The third objective can be attained only by increasing N, and the fourth objective can be realized by increasing N or a. By understanding of the effects of the design parameters, a guideline for optimal design was suggested, which also incorporates practical conditions. The most important point is to use the largest number of elements practically possible, since the main lobe width remains the same for constant aperture length while increased N reduces the side lobe levels and boosts the pressure in the steering direction.
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