The distinguishing feature of the phased array ultrasonic testing is the computer controlled excitation of the individual elements in a multi-elements probe. The excitation of these multiple piezo composite elements generates a focused ultrasonic beam, allowing the dynamic modification of the beam parameters such as angle, focal distance and focal spot size through software.

An array of transducer elements in which the timing of the elements excitation can be individually controlled to produce certain desired effects, such as steering the beam axis or focusing the beam.