Controlled transmission of multiband acoustic waves based on composite resonant cavities.

Previous studies have introduced topological concepts to the field of acoustics, greatly contributing to the development of acoustic wave-controlled transmission. It has evolved from acoustic wave transmission in a single frequency band to low-frequency and multiband transmission. This paper presents research on acoustic wave transmission control and the observation of transmission process properties. The paper proposes an acoustic topological insulator based on a composite resonant cavity that can change its topological boundary state and achieve controlled transmission of acoustic waves by adjusting the scatterer's rotation angle. At the same scale, this structure has a high internal space utilization and can make full use of the rotational scattering mechanism. In an air environment, the structure can create an acoustic topological transmission channel that can transmit acoustic waves in four bands. It has the advantage of having a wide frequency band. Furthermore, this study investigates the impact of channel defects on the transmission of acoustic waves, highlighting the fault-tolerant nature of these topological channels. These properties make it possible to control sound wave transmission along a predetermined path. These findings support the advancement of controllable acoustic wave transmission, which holds promise for applications in acoustic signal processing, acoustic stealth, and other related fields. [ABSTRACT FROM AUTHOR]