Directional sound transmission using ultrasonic array

• Main Author: Tan, Desmond Jun Quan
• Other Authors: Li King Ho Holden
• Format: Final Year Project
• Language: English
• Published: Nanyang Technological University 2022
• Subjects: Engineering::Mechanical engineering
• Online Access: https://hdl.handle.net/10356/157724
• Institution: Nanyang Technological University

High power non-lethal acoustic hailing devices are used for directional acoustic air transmission to incapacitate targets at a distance and are engaged in military, homeland security and law enforcement operations. A previous project study demonstrated two beams directional acoustic air transmission, with an array of commercial 40 kHz piezoelectric ultrasonic transducer and narrow frequency bandwidth of about 2.5kHz, showing limited audible sound fidelity needed for directional communication. This project studied the utilization of electrostatic ultrasonic transducers, having higher frequency response and wider frequency bandwidth, to build the transducer arrays for directional acoustic transmission. However, the construction of the only commercial electrostatic ultrasonic transducer, SensComp Series 600 50kHz Ultrasonic Transducer, makes them difficult to be incorporated into large transducer array. The emphasis of this project focused on the feasibility study of using additive manufacturing methods, especially 3D printing technology, to fabricate air coupled electrostatic ultrasonic transducer arrays. The basic internal structure requirement of the oscillation membrane and cavity gap dimension in commercial electrostatic ultrasonic generation was studied. A proof-of-concept (POC) air coupled electrostatic ultrasonic transducer (EUT) array design was developed in this project. The corresponding manufacture and assembly procedures were proposed for fabrication with 3D printing technology. The constituting parts of this design were then fabricated using the in-house 3D printer. The EUT array was then assembled for evaluation. Unfortunately, the performance of the prototype 3D printed electrostatic ultrasonic transducer array was not able to be tested due to lack of suitable testing equipment and must be the carried by the future project team.