Experiment study of double-layer membrane acoustic metamaterials with a compact magnet for low frequency wideband transmission loss

Single layer tunable membrane acoustic metamaterial with magnet usually can achieve one low-frequency transmission peak at the same time. To further increase its bandwidth, a double-layer membrane acoustic metamaterial (DMAM) with a compact magnet is proposed in this paper to implement a compact design for transmission loss at multiple low frequencies. This DMAM comprises two interval membranes and a compact magnet, each membrane has a centralized light iron pallet, on which exists different magnetic effect. The performance of the DMAM is investigated detailly by experiments. The results demonstrate that a reasonable design of distance between the members and the magnet can easily realize unity multiple transmission loss peaks which make the wideband available, due to the regime of different nonlinear magnetic force affect.