An ultrasonic Gaussian transducer and its diffraction field: theory and practice

In this paper, the authors present a novel way to describe the diffraction field for a Gaussian source, which becomes a Gaussian itself. It is described by the Rayleigh surface integral based on the Huygens' theorem. The derivation does not require the parabolic approximation used by previous authors. An improved spherical button Gaussian transducer design also is presented to verify the theory. A theoretical principle of this design based on electromagnetic theory is developed. Both megahertz and kilohertz experimental results show that the sound fields generated by Gaussian transducers of this design agree very well with the theoretical predictions.