Laboratory characterization of electromechanical behaviour of Bessel array-transducer annuli for detection & imaging in biological media

X wave annular arrays, properly driven, could be extensively applied for medical imaging and detection. The main utility of such a device is to permit the achieving of good collimation in the ultrasonic beam maintained along certain depth. In order to generate these kinds of waves, it is necessary to precisely excite a radiating aperture in a Bessel-transducer way. The work aim is the characterization of the behavior of array annuli in a 2 MHz piezoelectric Bessel transducer. The analysis, in function of the frequency, of a basic electrical characterization, measuring the electrical complex admittance and the cross-coupling of the array elements, as well as the evaluation of the annuli emission impulse responses, are performed by employing an installation of own design (Videus-CSIC lab), reciently developed for: pulsed acoustic signals acquisition, efficient array driving and advanced processing. Knowing the response of each one of elements in this type of array, it is already possible the achieving of a correct design of the especial multichannel pulsed electrical driving needed to generate limited diffraction X-waves applicable in medicine.