How is the sound beam steered in phased array transducers?

In phased array transducers, the steering of the sound beam is achieved by varying the timing of the pulses sent to each individual piezoelectric element within the array. This technique involves producing a delay in the transmission of ultrasound pulses between adjacent elements. By adjusting these timing delays, the ultrasound beams can be directed at different angles, allowing for a more flexible approach to scanning and imaging.

The ability to steer the beam is crucial for applications where dynamic imaging is required, such as in cardiac ultrasound, where the heart is constantly moving. Moreover, this capability enables the creation of images from multiple angles without the need to physically move the transducer.

In contrast, varying the amplitude of the pulses does not influence the direction of the beam; it primarily affects the strength of the signal. Keeping the pulses constant would negate the steering function altogether, as all elements would fire simultaneously, producing a beam directed straight ahead. Similarly, varying the frequency affects the resolution and penetration of the ultrasound, but it does not contribute to beam steering in the phased array configuration.