Acoustic Angle-Selective Transmission Based On Binary Phase Gratings

Angle-selective transmission is the function of allowing a wave of certain incident angle to pass through the system. It is one of the essential functions in analog wave filtering and control systems. However, the incident-angle dependence and frequency dependence of wave transmission in existing systems are always coupled and cannot be controlled individually without influencing the other. This work reports the design of an angle-selection system that can decouple the incident-angle dependence and frequency dependence in acoustic transmission. The system is formed by the combination of two binary phase gratings with different grating periods. It selects not only the angle of incident wave, but also the frequency. The selected angle and frequency can be tuned independently by changing different geometric parameters in the binary phase gratings. The designed double grating system has the potential to serve as the building elements to construct arbitrary wave-filtering systems in the frequency-angle space, such as the broadband angle-selection system.