Enhancement of convergence efficiency for airborne ultrasonic self-bending beam with phase-modulating reflector

Abstract Acoustic self-bending beams for airborne ultrasound are highly expected to expand the capabilities of existing acoustic applications. Our previous study has implemented amplitude control based on Airy function achieve an ultrasonic beam in air. However, lacks sound pressure convergence into main lobe. To improve convergence, we propose using a reflector phase modulation. In this study, used and developed that incorporates different heights spatial distribution. Using proposed demonstrated experimentally. addition, compared modulation, modulation improved efficiency level by more than 6 dB at distances 0.7 m 1.0 from emitter.