Design and Construction of a 2-D Phased Array Ultrasonic Transducer for Coupling in Water

摘要

Two-dimensional phased array transducers can deflect and focus the ultrasonic beam in a volumetric space, making a 3-D image reconstruction. In underwater media with low or no visibility, where underwater optical cameras become inefficient, this is an alternative approach to be used as tridimensional sonar. This paper presents the design, construction and characterization of a two-dimensional phased array ultrasonic transducer prototype for coupling in water. The transducer has sixteen elements arranged in a square matrix of 1-3 piezocomposite operating at 500 kHz. Improvements in sensitivity to echoes were reached with a quarter wavelength-thick matching layer and series inductors. Three types of backing layer material were simulated and tested for optimization of pulse-echo response: air, water and fiberglass. Images of objects at up to one-meter distance using the SAFT and TFM techniques were made, shown be feasible the use of the prototype constructed in underwater applications, like forward looking sonar and others in shallow waters.