BROADBAND TRANSDUCER

ACOUSTIC PROJECTOR TRANSDUCERS ARE THE PERFORMANCE LIMITING SUBSYSTEM FOR MANY ACTIVE UNDERWATER SOUND SYSTEMS. SIGNAL PROCESSING DEVELOPMENTS AND UNDERWATER ACOUSTIC RECEIVER DEVELOPMENTS HAVE DRAMATICALLY IMPROVED THE PERFORMANCE OF SONAR SYSTEMS SINCE WORLD WAR II. TRADITIONALLY, PROJECTOR AND RECEIVER TRANSDUCERS HAVE BEEN USED RECIPROCALLY WITH SATISFACTORY PERFORMANCE. HOWEVER, SOME OF THE MATERIALS AND MANY OF THE DESIGN INNOVATIONS THAT HAVE BEEN USED TO BROADEN THE BANDWIDTH AND IMPROVE THE GENERAL PERFORMANCE OF RECEIVERS ARE NOT APPLICABLE TO PROJECTOR TRANSDUCERS. THE DESIGN OF EFFICIENT SONAR PROJECTORS RELIES UPON OPERATION OF THE DEVICE AT OR NEAR THE RESONANT FREQUENCY OF THE TRANSDUCER. THE TRADITIONAL TRADEOFF FOR PIEZOELECTRIC OR MAGNETOSTRICTIVE PROJECTOR TRANSDUCERS HAS BEEN TO SACRIFICE OUTPUT EFFICIENCY AND SIZE FOR BANDWIDTH. A PROJECTOR DESIGN IS AVAILABLE WHICH OVERCOMES THE SEVERITY OF THIS COMPROMISE. THE COMPOSITE TRANSDUCER DESIGN IS DESCRIBED IN THE FOLLOWING PROPOSAL. A FEASIBILITY STUDY AND EXPERIMENTAL PROGRAM IS PROPOSED WHICH WILL SERVE TO DEMONSTRATE THE TRANSDUCER CONCEPT. THE PHASE I OBJECTIVES ARE: 1) DEFINE THE PROJECTOR REQUIREMENTS, 2) ASSESS THE CURRENT TECHNOLOGY, 3) ANALYTICALLY COMPARE SEVERAL NEAR TERM ALTERNATIVES, 4) PERFORM A CONCEPT TRADEOFF STUDY, 5) IDENTIFY KEY TECHNOLOGY ISSUES, 6) PERFORM AN EXPERIMENTAL PROOF OF PRINCIPLE, 7) PREPARE A DEVELOPMENT PLAN FOR ENGINEERING DEVELOPMENT OF THE CONCEPT.