How are sound beams focused in linear phased array transducers?

How are sound beams focused in linear phased array transducers?

• A. Mechanically
• B. Electronically
• C. Optically
• D. Magnetically

Answer: (B)

In a linear phased array, focusing is done electronically through beamforming. Each element is driven with a precise time delay so that the ultrasound waves from all elements arrive in phase at a chosen point, producing constructive interference that forms a narrow, focused beam. By adjusting these delays, the focus can be placed at different depths (dynamic focusing) and the beam can be steered across the image without moving the transducer. This electronic approach contrasts with mechanical focusing, which uses curved elements or lenses, and with optical or magnetic methods, which aren’t used to focus ultrasound in this context.

In a linear phased array, focusing is done electronically through beamforming. Each element is driven with a precise time delay so that the ultrasound waves from all elements arrive in phase at a chosen point, producing constructive interference that forms a narrow, focused beam. By adjusting these delays, the focus can be placed at different depths (dynamic focusing) and the beam can be steered across the image without moving the transducer. This electronic approach contrasts with mechanical focusing, which uses curved elements or lenses, and with optical or magnetic methods, which aren’t used to focus ultrasound in this context.