Parallel Helmholtz resonators for a planar acoustic notch filter
Parallel Helmholtz resonators for a planar acoustic notch filter
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DOI：
10.1063/1.4904509
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发表时间：
2014-12-15
影响因子：
4
通讯作者：
Shimoyama, Isao
中科院分区：
文献类型：
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作者：
Isozaki, Akihiro;Takahashi, Hidetoshi;Shimoyama, Isao
本文报道了一种在陷波频率处具有亚波长厚度的声平面陷波滤波器。研制的陷波滤波器由多个球形亥姆霍兹谐振器(HR)组成，这些谐振器连接在平板上的一个孔上。HR被放置在正多边形面内顶点处。模拟的压力分布表明，这种均匀排列的HRs提高了消声效果，因为HRs发出的均匀外加的波对短孔(在这种情况下，孔洞的长度是亚波长)的横截面起到抵消波的作用。无论连接到孔的HR的数量如何，从HR发出的总压力是相等的。因此，HRs的布置是实现平面陷波滤波器的关键。模拟的透射率谱表明，透过率的凹陷深度随着均匀排列的HRs数目的增加而增加。我们证实，由1到6个HR组成的制作的陷波滤光片的实验透射谱与模拟的透射谱是一致的。本研究中提出的滤波片的设计和相应的分析应该会推动薄型滤波片的进一步发展。(C)2014 AIP出版有限责任公司。
This paper reports on an acoustic planar notch filter with a sub-wavelength thickness at the notch frequency. The developed notch filter consists of a number of spherical Helmholtz resonators (HRs) connected to a hole created in a plate. The HRs were placed at the in-plane vertices of a regular polygon. A simulated pressure distribution revealed that this uniform arrangement of HRs improves the silencing effect because the uniform applied waves emitted from the HRs act as canceling waves to the cross-section of the short hole (in this case, the length of the hole is sub-wavelength). The total pressure emitted from the HRs is equal regardless of the number of HRs connected to the hole. Therefore, the arrangement of HRs is essential for realizing a planar notch filter. Simulated transmittance spectra showed that the depth of the dip in the transmittance increased with the number of uniformly arranged HRs. We confirmed that the experimental transmittance spectra of fabricated notch filters, which consisted of between one and six HRs, agreed with the simulated transmittance spectra. The design of the acoustic filter presented in this study and the corresponding analysis should motivate further development of thin acoustic filters. (C) 2014 AIP Publishing LLC.