Microperforated panel (MPP) absorber progress has continued with various configurations for a relatively narrow bandwidth. Serial, parallel, and a combination of serial and parallel (hybrid) configurations of MPPs have been proposed to address the bandwidth problem, and experimental results agree well with theoretical ones. However, considerable space is still required, particularly at low frequencies, because of the presence of a backing air cavity. This drawback has limited MPP applications for low-frequency noise control, where longer cavity depths are required. Therefore, in this study, a coiling structure was introduced on the backing air cavity to obtain a thinner MPP for the same targeted operating frequency. Moreover, a parallel configuration consisting of several sub-MPPs was utilized to excite multiple resonances to obtain an overall wider absorption bandwidth. Minute holes were applied to avoid the considerable dips that are generally present in such a configuration. Thin and broadband MPPs were developed, and theoretical and experimental results are provided.

微穿孔板 (MPP) 吸收器的进展一直在不断发展，具有相对较窄的带宽的各种配置。已经提出了 MPP 的串行、并行以及串行和并行（混合）配置的组合来解决带宽问题，并且实验结果与理论结果非常吻合。然而，仍然需要相当大的空间，特别是在低频时，因为存在背衬空气腔。这个缺点限制了 MPP 在低频噪声控制中的应用，在这些应用中需要更长的腔深度。因此，在本研究中，在背衬气腔上引入了线圈结构，以在相同的目标工作频率下获得更薄的 MPP。而且，由几个子 MPP 组成的并联配置用于激发多个共振以获得更宽的整体吸收带宽。应用了微小的孔来避免这种配置中通常存在的相当大的倾斜。开发了薄型和宽带 MPP，并提供了理论和实验结果。