Quasi-nondiffracting beam of Hankel type produced by weighted conical ultrasound transducers

The field of a J₀ nondiffracting beam can be regarded as the superposition of two Hankel fields each corresponding to the converging and the diverging waves. The authors show that, for a limited aperture, a quasi-nondiffracting ultrasonic beam, partially of Hankel type, is produced by a conical transducer with weighted amplitude distribution. The beam possesses reduced sidelobe characteristics in the vicinity of the transducer