GRIN metamaterial generalized Luneburg lens for ultra-long acoustic jet

Lu, Chunyao; Yu, Run; Ma, Qiujun; Wang, Kangyu; Wang, Jing; Wu, Dawei

doi:10.1063/5.0044436

Cited by 21 publications

(7 citation statements)

References 36 publications

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“…The equivalent fluid model is defined with the parameters that can be calculated by the Eqs. ( 9) to (11). These calculated values have been used in FEM simulations as shown in Fig.…”

Section: Methodsmentioning

confidence: 99%

“…Numerous uses for the deep-subwavelength thick broadband low-frequency sound absorber can be found in acoustic cloaking and noise reduction. An acoustic metamaterial is an excellent candidate to tackle all challenges with careful design of structures that may possess extraordinary acoustic properties like broadband noise absorption [1][2][3][4][5] , sound insulation [6][7][8] , noise cloaking properties 9,10 , acoustic jetting properties 11 etc. Acoustic metamaterials are well known as artificial or man-made structures that may be programmed through negative effective density 12,13 , negative effective modulus 14,15 , and simultaneous negative modulus and density [16][17][18] .…”

mentioning

confidence: 99%

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Hybrid fractal acoustic metamaterials for low-frequency sound absorber based on cross mixed micro-perforated panel mounted over the fractals structure cavity

Singh

Prakash²,

Bhattacharya

2022

Sci Rep

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The proposed work enumerates a hybrid thin, deep-subwavelength (2 cm) acoustic metamaterials acting as a completely new type of sound absorber, showing multiple broadband sound absorption effects. Based on the fractal distribution of Helmholtz resonator (HRs) structures, integrated with careful design and construct hybrid cross micro-perforated panel (CMPP) that demonstrate broad banding approximately one-octave low-frequency sound absorption behavior. To determine the sound absorption coefficient of this novel type of metamaterial, the equivalent impedance model for the fractal cavity and the micro-perforated Maa’s model for CMPP are both used. We validate these novel material designs through numerical, theoretical, and experimental data. It is demonstrated that the material design possesses superior sound absorption which is primarily due to the frictional losses of the structure imposed on acoustic wave energy. The peaks of different sound absorption phenomena show tunability by adjusting the geometric parameters of the fractal structures like cavity thickness ‘t’, cross perforation diameter of micro perforated panel, etc. The fractal structures and their perforation panel are optimized dimensionally for maximum broadband sound absorption which is estimated numerically. This new kind of fractals cavity integrated with CMPP acoustic metamaterial has many applications as in multiple functional materials with broad-band absorption behavior etc.

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“…The equivalent fluid model is defined with the parameters that can be calculated by the Eqs. ( 9) to (11). These calculated values have been used in FEM simulations as shown in Fig.…”

Section: Methodsmentioning

confidence: 99%

mentioning

confidence: 99%

Hybrid fractal acoustic metamaterials for low-frequency sound absorber based on cross mixed micro-perforated panel mounted over the fractals structure cavity

Singh

Prakash²,

Bhattacharya

2022

Sci Rep

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show abstract

“…Figure 1 shows that the three energy bands are approximately straight lines around 3500 Hz. Therefore, the phase velocity which is nearly equal to the group velocity [17,24,36] can be directly calculated by v p = 2pf/k along the C À X direction, where k is the reciprocal wavenumber. The effective refractive index is defined as n eff = v w /v p , where v w is the sound velocity in water.…”

Section: Luneburg Lens Based On Phononic Crystalsmentioning

confidence: 99%

“…When the working environment is air, the fluid-solid coupling is always ignored [20,21], so Yu et al [22] redesigned an underwater Luneburg lens for enhancing the focused signal at a center frequency of 180 kHz. Allam et al [23] and Lu et al [24] provided a 3D-printed approach to replace the metallic structure for acoustic wave focusing using the Luneburg lens [25]. 3D-printed is the fastest way to fabricate the Luneburg lens if the hydrostatic pressure is ignored.…”

Section: Introductionmentioning

confidence: 99%

2D phononic-crystal Luneburg lens for all-angle underwater sound localization

Ruan

Liang

2022

Acta Acust.

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Phononic crystals are well known for acoustic wave manipulation which may have potential application in an underwater acoustic detection system. In this work, we design and simulate a two-dimensional Luneburg lens based on gradient-index (GRIN) phononic crystal that is composed of PLA-Air inclusion, and a novel application of GRIN phononic crystals is proposed to sound localization. The Luneburg lens has a broadband working range, from 1500 Hz to 7500 Hz, for acoustic wave focusing with sensitive directivity and signal-to-noise improvement. By searching maximum wave intensity’s position of the focusing beam, the propagating direction of an unknown sound wave can be directly recognized covering 360°. Besides, we redesign the conventional square-lattice Luneburg lenses using annular lattices for better performance. The annular-lattice Luneburg lens overcomes the weakness of configuration defect due to the square lattice. The numerical results show that the redesign Luneburg lenses have high accuracy for distance measurement from 5 m to 35 m through the triangulation location. In a word, this work tries to explore a novel application of phononic crystals in underwater acoustic positioning and navigation technology.

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“…Negative permeability, permittivity and refractive index are some exclusive properties of the metamaterial that can be used for various applications in communication systems of microwave frequencies. Antenna performance improvement 1 – 3 , radiation reduction 4 , 5 , design of absorber 6 , 7 , sensors 8 , 9 , high-frequency communications 10 , 11 , solar energy harvesting 12 , 13 , electromagnetic shielding 14 , metamaterial lenses 15 , etc. are some prominent applications of the metamaterial.…”

Section: Introductionmentioning

confidence: 99%

Gap coupled symmetric split ring resonator based near zero index ENG metamaterial for gain improvement of monopole antenna

Moniruzzaman

Islam

Samsuzzaman

et al. 2022

Sci Rep

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In this article, a symmetric split ring resonator (SRR) based metamaterial (MTM) is presented that exhibits three resonances of transmission coefficient (S21) covering S, C, and X-bands with epsilon negative (ENG) and near zero index properties. The proposed MTM is designed on an FR4 substrate with the copper resonator at one side formed with two square rings and one circular split ring. The two square rings are coupled together around the split gap of the outer ring, whereas two split semicircles are also coupled together near the split gaps. Thus, gap coupled symmetric SRR is formed, which helps to obtain resonances at 2.78 GHz, 7.7 GHz and 10.16 GHz with desired properties of the MTM unit cell. The MTM unit cell's symmetric nature helps reduce the mutual coupling effect among the array elements. Thus, different array of unit cells provides a similar response to the unit cell compared with numerical simulation performed in CST microwave studio and validated by measurement. The equivalent circuit is modelled for the proposed MTM unit cell in Advanced Design System (ADS) software, and circuit validation is accomplished by comparing S21 obtained in ADS with the same of CST. The effective medium ratio (EMR) of 10.7 indicates the compactness of the proposed MTM. A test antenna is designed to observe the effect of the MTM over it. Numerical analysis shows that the proposed MTM have an impact on the antenna when it is used as the superstrate and helps to increase the gain of the antenna by 95% with increased directivity. Thus, compact size, high EMR, negative permittivity, near zero permeability and refractive index makes this MTM suitable for S, C and X band applications, especially for antenna gain with directivity enhancement.

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GRIN metamaterial generalized Luneburg lens for ultra-long acoustic jet

Cited by 21 publications

References 36 publications

Hybrid fractal acoustic metamaterials for low-frequency sound absorber based on cross mixed micro-perforated panel mounted over the fractals structure cavity

Hybrid fractal acoustic metamaterials for low-frequency sound absorber based on cross mixed micro-perforated panel mounted over the fractals structure cavity

2D phononic-crystal Luneburg lens for all-angle underwater sound localization

Gap coupled symmetric split ring resonator based near zero index ENG metamaterial for gain improvement of monopole antenna

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