  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
