Realization of manipulating acoustic surface waves radiation direction with rectangular-groove structure

Acoustic surface waves (ASWs) can be generated through a one-dimensional array of grooves. Sound can be collimated by ASWs. However, in previous studies, the groove period and grating period have been the same. In this work, we propose a structure where the groove period is different from the grating period, and collimates sound waves with very small side lobes. The structure can alter the acoustic wave radiation direction by manipulating ASWs and the relationship between the radiation direction and the frequency for different groove depths are investigated. Furthermore the incident direction of the sound wave, which can be coupled into ASWs, can be manipulated by changing the period of rectangular grating. We theoretically illustrate the physical mechanism of controlling the ASW radiation direction by wave-number analysis. These theoretical predictions are verified using numerical simulations. Using this proposed structure, we can manipulate the ASW radiation direction, which is very important for practical applications of directional acoustic propagation.