Which description best matches how a phased array transducer operates?

• A. Electronically focused in two dimensions and mechanically steered
• B. Electronically focused along the length of the array, mechanically focused along the elevation dimension (width) and electronically steered
• C. Electronically focused along the elevational dimension of the array, mechanically focused along the length of the array and unsteered
• D. Mechanically focused in two dimensions and mechanically steered

Answer: (B)

The essence is how a phased array shapes and moves the beam using timing, without moving the probe. A phased array achieves focusing and steering primarily through electronic delays across the elements. This lets the beam be focused in the plane of the array (along its length) and steered to different angles while the aperture is driven with precise timing. The elevational dimension (the out-of-plane thickness) isn’t typically controlled electronically with a single-row array; it’s usually set by the physical arrangement of the elements and often refined with mechanical means (lens or curved geometry) to provide elevation focusing. So the description that matches this behavior is electronic focusing along the length of the array, mechanical focusing in the elevational direction, and electronic steering.