Design and characterization of immersion ultrasonic transducers for pulsed regime applications

Abstract

Ultrasonic transducer design is focused to maximize performance in specific applications, usually leading to a complex design and expensive construction and assembly. With the aim to overcome this drawback, a generalpurpose immersion ultrasonic transducer for pulsed regime applications have been developed. The design of each element of the transducer is described in this paper, wherein materials and geometries for each part have been recommended. A simple theoretical model have been proposed in order to predict the form of the received electric signal in the target transducer. The model is based in the assumption that the piezoelectric element acts as an underdamped oscillator, forced by the acoustic field coming from the propagation medium. Excellent agreement between the experimental measurements and the analytical model is achieved. Electrical impedance measurements reveal negligible differences between the resonance frequency of the active element and that of the assembled transducer. The designed devices have been characterized in water, using two identical transducers placed face to face with changeable orientation. Experimental results show a highly linear response and the generation of a collimated acoustic field. The effects of the thickness of the matching layer on the transmission coefficient have been also studied, resulting in a smooth decrease in the received amplitude, which may significantly lower largescale production costs. . contributed in the design, modeling and assembly of the transducer, performed experimental measurements, data analysis, and wrote the paper. Diego A. O. contributed significantly to the design and fabrication of the transducers, and provided helpful scientific support. Laura R. S. assembled the transducers and performed experimental measurements. Jose E. G. have supervised this work, which included participating in discussions, planning and designing the experiments and refining the manuscript.

Temperature Effects in an Acousto-Optic Modulator of Terahertz Radiation Based on Liquefied SF6 Gas

“…Similarly, when the radiation is incident on the AO cell at the Bragg angle, the diffracted beam is observed only for a narrow ultrasound frequency band. The resonant frequency is determined by the thickness d of the sound transducer: [ 18 ]. Here is the sound velocity in the material of the sound transducer.…”

Characterization of a Piezoelectric Acoustic Sensor Fabricated for Low-Frequency Applications: A Comparative Study of Three Methods

“…Ultrasound measurement systems have gained significant popularity over the last few decades, and their applications span across several industries, including non-destructive testing (NDT) for predictive maintenance and fault detection [1][2][3][4][5][6][7] medical acoustics for diagnosis and ultrasound scans [8][9][10], and communication and monitoring of marine environments [11][12][13][14][15][16]. Piezoelectric transducers are the primary means of generating acoustic energy in most of these systems.…”

Modeling Pulsed High-Power Spikes in Tunable HV Capacitive Drivers of Piezoelectric Wideband Transducers to Improve Dynamic Range and SNR for Ultrasonic Imaging and NDE

“…This suggests, in the finally received ultrasonic signals for HR imaging and NDE, improvements in SNR and NDRA of up to 38 (45) dB, which could be extended up to 43 (50) dB using 700 V spikes (if this voltage was electrically supported by the transducers), without using any amplification, averaging, or filtering. These huge voltages in the received pulsed signals must be compared with those acquired in classical ultrasonic pulse-echo imaging or T-T NDE cases from inside solid or liquid inspected media, which are usually below values of 1 V pp or even of 100 mV pp [26][27][28][29][30][31]. Therefore, from our highly efficient driver (demonstrated by their excellent results) it can be predicted that its circuital topology (deeply analyzed in this paper) will originate pulsed high-power driving spikes very adequate for a hugely efficient driving of wideband PZT transducers having very low motional input resistance, through a low series output impedance (≈1-2 Ω).…”