Functional composites for sensors, actuators and transducers

Following the trend in structural applications, composite structures are be ing used more commonly in transducer applications to improve acoustic, mech anical and electrical performance of piezoelectric devices. Functional comp osite transducers for actuators and sensors generally consist of an active ceramic phase incorporated with a passive polymer phase, each of which has a phase transition associated with it. In this paper, several polymer-piezo electric ceramic composite transducers, mostly designed for sensing hydrost atic waves, are discussed based on the connectivity of the constituent phas es. Also discussed are some recent examples of metal-ceramic composites, an d single element ceramic transducers with modified shapes for improved perf ormance. A comparison of these designs is given based on their hydrophone f igure of merit (d(h).g(h)) (C) 1999 Elsevier Science Ltd. All rights reserv ed.