The influence of coherent coupling effects on the sound absorption performance of acoustic metasurfaces

In recent years, acoustic metasurfaces have gained significant attention as thin sound-absorbing materials. Due to their high design flexibility, they are expected to be applied in a wide range of acoustic applications. However, when multiple resonators are arranged in parallel, coherent coupling effects can occur, leading to deviations in the resonance frequencies and absorption coefficient from the designed values. Although several studies have been conducted on the design of acoustic metasurfaces and their associated coherent coupling effects, most of them have focused on the low-frequencyrange, with relatively few investigations targeting the mid- to high-frequency range. In this study, we aimed to improve the acoustic absorption performance of metasurfaces by analyzing and evaluating the coherent coupling effects of slit-type resonators in the mid- to high-frequencyrange through both numerical simulations and experiments. The results confirmed the presence of coherent coupling effects in both approaches, with consistent trends observed. Furthermore, it was confirmed that the absorption performance of individual resonators is affected by their frequency spacing and spatial arrangement, both of which were found to have a significant influence on the coupling effects.