Which statement describes a phased array transducer?

Which statement describes a phased array transducer?

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

Answer: (D)

A phased array transducer shapes and steers the ultrasound beam by controlling the timing of signals to its multiple elements. Focusing in the plane of the array (along its length) is achieved electronically by applying delays that make the wavefront converge at a focal point. The elevational dimension, which runs perpendicular to that plane, is typically focused with the transducer’s physical lens or geometry, i.e., mechanically. Steering is done electronically by adjusting the delays across the elements to tilt the beam without moving the probe. The combination described—electronic focusing along the length, mechanical focusing in elevation, and electronic steering—fits how a phased array transducer operates. If both dimensions were electronic, that would describe a different, usually 2D, array.

A phased array transducer shapes and steers the ultrasound beam by controlling the timing of signals to its multiple elements. Focusing in the plane of the array (along its length) is achieved electronically by applying delays that make the wavefront converge at a focal point. The elevational dimension, which runs perpendicular to that plane, is typically focused with the transducer’s physical lens or geometry, i.e., mechanically. Steering is done electronically by adjusting the delays across the elements to tilt the beam without moving the probe. The combination described—electronic focusing along the length, mechanical focusing in elevation, and electronic steering—fits how a phased array transducer operates. If both dimensions were electronic, that would describe a different, usually 2D, array.