Research Of Sharpening Directivity Of Piezoelectric Ultrasonic Transducer Array

Ultrasonic transducer array, whose function is to transfer high-frequency electric signal to ultrasound, is an important part of Acoustic Parametric Array. In the Acoustic Parametric Array, the ultrasound formed by the transducer array self-demodulates into hearable sound. Because the goal of the Acoustic Parametric Array is to form sound in a sharp direction, so the transducer array should have a sharp directivity. The aim of this thesis is to design a sharp directivity transducer array which is under a set requirement and the author introduces the idea of design, process of research and analysis of testing.Under the set requirement of the piezoelectric transducer array, the author first introduces the physical reason of forming the directivity of the array, and respectively researches the calculating method of annular and rectangular piezoelectric transducer arrays. The author then simulates the directivities of the arrays using Matlab software, analysis the factors making effect on the directivities when designing the arrays, points out the difference between the directivities of these two kinds of array and at last makes the final choice. Through collecting information, the author points out that in order to enhance the practical directivity of the piezoelectric ultrasonic transducer array, the transducers should be tested and selected. Then the author introduces the resonance character, dynamic character, centralized parametric equivalent circuit and the admittance & impedance characters of the piezoelectric ultrasonic transducers. The author researches the testing method of the piezoelectric ultrasonic transducers, tests them using an Impedance Analysis System, researches the parameters making main effect on the output result of the transducer and selects the transducers according these important parameters. The selected transducers and the designed transducer array are used to make the real electric circuit board and the electric circuit board is put into the Acoustic Parametric Array system for testing.In the end of this thesis, the author sums up all the researching work, points out the solving method for the existing problems and makes a scheme for the future work.