<title>Design and evaluation of ultrasonic arrays using 1-3 connectivity composites</title>

Abstract

Ceramic-epoxy composite transducers, in the form of a matrix of piezoceramic rods embedded in an epoxy substrate, offer significant advantages for sonar array design in the frequency range 100 kHz - 2 MHz. Good matching to the water load, coupled with high sensitivity, low lateral crosstalk, and wideband performance are extremely attractive features for modern array design. This paper describes a simulation design strategy for both 1-D and 2-D composite array configurations, with specific emphasis placed on the latter structure. The development and subsequent evaluation of an interactive software design tool for the performance assessment of composite arrays, and in particular, their imaging potential for applications in underwater visualization systems, in which the array will be configured as part of a scanning system, is investigated. Firstly, finite element analysis (FEA) is used to evaluate the various factors which relate to the micro-structure of the composite material i.e., volume fraction, and the size and number of ceramic rods under the electrode. A linear systems approach is then adopted to investigate the macro-structure of the composite transducer, and considers the effects of material composition; ceramic-epoxy volume fraction and transducer backing impedance. Finally, the scattering responses from arbitrary target structures are considered, using practical array dimensions, as specified by the FEA and linear systems analysis. The model employed for target scattering is capable of simulating a wide range of composite configurations, and also of varying mechanical and electrical load conditions. In addition, it permits the analysis of realistic target scenarios, comprising an arbitrary arrangement of arcs, circles, and rectangles. A range of examples are presented, including both 1-D and 2-D transducer array configurations, and a selection of imaging results obtained via a 10 X 10 2-D array operating at 1.2 MHz. Good agreement between theory and experiment is obtained.© (1992) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.