Electroacoustic Transducer for the Parametric Generation of Ultrasound

An electro-acoustic transducer for parametric generation of ultrasound comprising:

• two generators of electrical oscillations, the two generators having their outputs connected via a linear adder to an input of a pulse modulator;
• the pulse modulator controlled by a pulse generator;
• a power amplifier;
• and
• a notch filter having an output connected to an input of a first piezoelectric transducer, the first piezoelectric transducer having a radiating aperture which is a section of a convex spherical surface;
• a second piezoelectric transducer with a concave spherical aperture surface, the second piezoelectric transducer being connected to the output of the notch filter;
• and
• a supporting structure of a cylindrical shape supporting the first and second piezoelectric transducers, wherein for both of the piezoelectric transducers a diameter D of the apertures, an average wavelength λ for a range of emitted pump signals, radii of curvature R0, focal lengths F0, radii r0 of focal spots are chosen identical and are related as r0×R0=0.61×λ×F0, and wherein the first piezoelectric transducer is provided with an open axial hole radius r=(2÷3)×r0 in a central portion of the convex spherical surface of the radiating aperture.