Low-Frequency Low-Reflection Bidirectional Sound Insulation Tunnel with Ultrathin Lossy Metasurfaces

We report both numerical and experimental constructions of a tunnel structure with low-frequency low-reflection bidirectional sound insulation (BSI). The designed was constructed from pair lossy acoustic metasurfaces (AMs), which consists six ultrathin coiled unit cells, attached on sides. Based the generalized Snell?s law phase modulations for AMs, BSI based reflections blind areas created by AMs. obtained transmittances were almost same incidences sides lower than ?10 dB in range 337–356 Hz. simulated measured results agreed well each other. Additionally, we show that characteristic can be simultaneously thermoviscous energy loss channels cells. Finally, an interesting application open-window is further detail. proposed AMs has advantages thickness (about ?/35), BSI, high-performance ventilation, may have potential applications architectural acoustics noise control.