ULTRASONIC NONDIFFRACTING TRANSDUCER

摘要

An ultrasonic transducer for use in medical imaging systems includes a piezoelectric element having an active electrode formed as a series of concentric annular segments. Each segment is separately driven by a transmitter in which the amplitude and phase of the drive signals produce an ultrasonic wave having a pressure profile that approxinmates a zeroth order Bessel function. A nondiffracting beam of ultrasonic waves is produced.