Waveform-preserved unidirectional acoustic transmission based on impedance-matched acoustic metasurface and phononic crystal

Abstract

The waveform distortion happens in most of the unidirectional acoustic transmission (UAT) devices proposed before. In this paper, a novel type of waveform-preserved UAT device composed of an impedance-matched acoustic metasurface (AMS) and a phononic crystal (PC) structure is proposed and numerically investigated. The acoustic pressure field distributions and transmittance are calculated by using the finite element method. The subwavelength AMS that can modulate the wavefront of the transmitted wave at will is designed and the band structure of the PC structure is calculated and analyzed. The sound pressure field distributions demonstrate that the unidirectional acoustic transmission can be realized by the proposed UAT device without changing the waveforms of the output waves, which is the distinctive feature compared with the previous UAT devices. The physical mechanism of the unidirectional acoustic transmission is discussed by analyzing the refraction angle changes and partial band gap map. The calculated transmission spectra show that the UAT device is valid within a relatively broad frequency range. The simulation results agree well with the theoretical predictions. The proposed UAT device provides a good reference for designing waveform-preserved UAT devices and has potential applications in many fields, such as medical ultrasound, acoustic rectifiers, and noise insulation.

Broadband Bidirectional and Multi-Channel Unidirectional Acoustic Insulation by Mode-Conversion Phased Units

“…Based on the mode-conversion phased unit, we design two types of phased array lenses with two types of sound insulation effects, such as BAI, UAI and reversed UAI. Compared with other types of sound insulation lenses based on the phase modulation (Song et al, 2016;Zhao et al, 2017;Yu et al, 2019), the proposed lenses have the typical advantages of single-layer planar structure, multi-functional sound insulation, and broad bandwidth.…”

Research progress of acoustic metasurface in China

“…The transmitted wave manipulation of the AMS with periodical slits is theoretically revealed by mode-coupling theory. Using the similar periodic cut-through slit unit, the wide band acoustic cloak and diode are designed by Wang et al [37][38][39], and the acoustic one-way propagation range is from 4350 to 5500 Hz and 5100 to 8400 Hz in air, respectively.…”

High-efficiency unidirectional wavefront manipulation for broadband airborne sound with a planar device

“…[1][2][3][4] In acoustics, the attempts to break the symmetry in sound propagation began with the emergence of acoustic diode that used nonlinearity to break the limitation of reciprocity, offering the possibility to design novel functional devices that only allowed acoustic wave to pass along one particular direction and may enable special application in various scenarios. [5,6] Later, different mechanisms were proposed for the purpose of further improving the performance of acoustic one-way devices by breaking the spatial symmetry instead of the time reversal symmetry, [7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23] giving rise to different designs featuring broad working bandwidths, [7,8,10,12,13,19,23] high forward transmission efficiencies, [7,8,11,12,14] compact sizes, [9,13,[15][16][17]20,22] planar profiles, [14][15][16]…”