Analysis of the electrostatic ultrasonic airborne actuator using the finite-difference time-domain method

Abstract

We have investigated the structure of an electrostatic airborne ultrasonic actuator by using the FDTD method. The actuator structure has low-mass pleat-fold diaphragms. The pleat designed 10 mm deep and 2 mm wide, vibrate at a frequency range of 10 kHz to 200 kHz. The diaphragms of the pleat vibrate and carry out high power and wide directivity ultrasonic sound waves from a narrow output opening end. We have found the correlation between the depth of the pleat and the wavelength that the sound pressure level had peak and dip depending on the frequency. Using numerical simulation by the FDTD method, the interference in the pleat animated and described visibly. Instead of the plane wave source that caused the interference of the sound source in the pleats, progressive wave sources have mitigated interference and gained higher outputs. In the FDTD simulation, progressive wave source at 200 kHz generated 73 dBSPL and about + 30 dBSPL higher compared to the plane wave when the vibration amplitude and velocity ...