USE OF COMPOSITE MATERIALS FOR A B-SCAN TRANSDUCER.

Several types of piezoceramic/polymer composites with 1-3 connectivity are being studied as ultrasonic biomedical transducers. Their underwater acoustic behavior has been studied at 1-5 MHz and these data are compared to the thickness mode figure of merit and other properties of composites. One composite disc 41-mm diam multiplied by 1-mm thick was flexible enough to form a concaved spherical cap with a 7. 5-cm radius. This transducer had a maximum response at 1. 5 MHz and was naturally matched at resonance to the 50- OMEGA impedance of the power supply. The one-half amplitude bandwidth was 1. 3 MHz but the time-domain signal exhibited some minor energy before and after the main pulse. A very high sensitivity composite material was also identified for future B-scan transducers.