Ultrathin multifunctional labyrinth metamaterial with efficient dual absorption of sound and electromagnetic waves

With the escalating severity of noise and electromagnetic pollution, the demand for high-efficiency integrated sound and electromagnetic wave absorption structures has become increasingly prominent. However, under the stringent requirement of lightweight design, the compact integration of these two functionalities into a single structure remains a key challenge. To address this issue, based on the structure-material-function integrated design concept, this study proposes a multifunctional labyrinth metamaterial (MLM) through the ingenious combination of labyrinth structures and wave-absorbing lattices. This design achieves the synergistic enhancement of acoustic and electromagnetic performances: the cover plate required for acoustic functionality serves as a wave-transparent structure, which significantly improves the electromagnetic impedance matching characteristics; meanwhile, the lattice needed for electromagnetic functionality provides an additional energy dissipation for acoustic absorption. Ultimately, with an ultrathin thickness of 16 mm, MLM successfully realizes broadband electromagnetic wave absorption in the frequency band of 2.72–18 GHz and broadband acoustic absorption in the frequency band of 380–460 Hz. This research provides a novel solution for noise and electromagnetic protection in high-end fields such as transportation, aerospace, and national defense, exhibiting significant application prospects.