What is the effect of increasing the active aperture by using many small elements with small pitch?

Increasing the active aperture by using many small elements with small pitch enhances both the focusing factor and beam steering capability. When the active aperture is enlarged, the system can achieve better spatial resolution and improved focus at various depths. This is primarily because a wider aperture allows for more constructive interference of sound waves, which leads to a sharper and more defined focus.

Furthermore, having many small elements close together (small pitch) improves the ability to steer the beam in different directions. The increased number of elements allows for finer control over the phase of each element, which is crucial for directing the beam precisely where it is needed. This capability is critical for applications requiring detailed inspection and accurate defect characterization in materials.

While larger apertures can lead to challenges such as potential grating lobes, the primary benefits are the enhancements in focusing and steering, making the chosen answer valid in the context of phased array technology.