Acoustic (Ultrasonic) Non-Diffracting Beams: Some theory, and Proposals of Acoustic Antennas for several purposes

TL;DR

This paper develops theoretical models and proposals for generating ultrasonic non-diffracting beams using acoustic antennas, with applications in remote sensing, detection, and mine explosion, emphasizing high-power transducers and beam resilience.

Contribution

It introduces new theoretical foundations and practical antenna designs for producing ultrasonic non-diffracting beams capable of resisting diffraction and attenuation in lossy media.

Findings

Feasible generation of non-diffracting ultrasound beams at 40 kHz with finite apertures.

Proposals for high-power acoustic transducers for remote detection and mine explosion.

Beams capable of resisting diffraction and attenuation in lossy environments.

Abstract

On the basis of suitable theoretical grounds, we study and propose Antennas for the generation, in Acoustics, of Non-Diffracting Beams of ultrasound. We start considering for instance a frequency of about 40 kHz, and foresee fair results even for finite apertures endowed with reasonable diameters (e.g., of 1 m), having in mind various possible applications, including remote sensing. Then, we discuss the production in lossy media of ultrasonic beams resisting both diffraction and attenuation. Everything is afterward investigated for the cases in which high-power acoustic transducers are needed (for instance, for detection at a distance -or even explosion- of buried objects, like mines). Keywords: Acoustic Non-Diffracting Beams; Truncated Beams of Ultrasound; Remote sensing; Diffraction, Attenuation, Annular transducers, Bessel beam superposition, High-power ultrasound emitters, Beams resisting diffraction and attenuation, Acoustic Frozen Waves, Detection of buried objects, Explosion of Mines at a distance