Enhanced Low‐Frequency Monopole and Dipole Acoustic Antennas Based on a Subwavelength Bianisotropic Structure

Jia, Yurou; Luo, Yan-Chun; Wu, Da‐Jian; Wei, Qi; Liu, Xiaojun

doi:10.1002/admt.201900970

Cited by 11 publications

(7 citation statements)

References 34 publications

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“…There are so many loudspeakers, and their sound control has reached perfection, although their size is usually much smaller than the wavelength. However, there are still few works on the influence of the environment on the emission of acoustic waves in the aspect in which is relevant for electromagnetic waves [212][213][214], although this is very important for the creation of effective small-sized sources of low-frequency sound.…”

Section: Acoustic Wave Emittersmentioning

confidence: 99%

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Control of the emission of elementary quantum systems using metamaterials and nanometaparticles

Климов¹

2021

Phys.-Usp.

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The most important direction in the development of fundamental and applied physics is the study of the properties of optical systems at nanoscales for creating optical and quantum computers, biosensors, single-photon sources for quantum informatics, DNA sequencing devices, detectors of various fields, etc. In all these cases, nanosize light sources such as dye molecules, quantum dots (epitaxial or colloidal), color centers in crystals, and nanocontacts in metals are of utmost importance. In the nanoenvironment, the characteristics of these elementary quantum systems—pumping rates, radiative and nonradiative decay rates, the local density of states, lifetimes, level shifts—experience changes, which can be used to create nanosize light sources with the desired properties. Modern theoretical and experimental works on controlling the emission of elementary quantum systems with the help of plasmonic and dielectric nanostructures, metamaterials, and metamaterial nanoparticles are analyzed.

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Section: Acoustic Wave Emittersmentioning

confidence: 99%

“…54c, the agreement between theory and experiment is good, and that is not surprising, since losses in the system are small, and acoustic waves are scalar. A study of a similar system with more complicated geometry was carried out in [213], where high values of the Purcell factor were also predicted.…”

Section: Acoustic Wave Emittersmentioning

confidence: 99%

Control of the emission of elementary quantum systems using metamaterials and nanometaparticles

Климов¹

2021

Phys.-Usp.

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“…[22,23] However, most acoustic metamaterials are designed in a way that makes it challenging for them to have a direct and immediate impact on real-world applications pertaining to the audio industry, with one possible exception being sound absorption. [24] On the one hand, despite the reduction of audio distortion [25] realized by the mitigation of high-frequency acoustical cavity-resonances through the addition of acoustic metamaterial-based absorbers in loudspeaker enclosures, the attempt to incorporate passive acoustic metamaterials [26][27][28][29][30][31][32][33] into the loudspeaker designs has seen very limited radiation enhancement at low frequencies due to the bulky size and the lack of consideration on the metamaterial-transducer coupling. On the other hand, though active acoustic metamaterial may offer a solution to a broadband radiation enhancement, [34] they often involve designs that are complicated to avoid instability and also require more power consumption.…”

Section: Introductionmentioning

confidence: 99%

Metamaterial‐Augmented Head‐Mounted Audio Module

Ji,

Zhao,

Yao

et al. 2023

Adv Materials Technologies

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Recent developments in metamaterial research have shown promising progress in overcoming the fundamental physical limitations of acoustics. While the majority of this research is curiosity‐driven and focused on fundamental physics, there has been a scarcity of acoustic metamaterials research that can have a direct and immediate impact on real‐world applications. In this study, an acoustic metamaterial inside a head‐mounted audio module is incorporate to achieve a 3–7 dB broadband sound pressure level (SPL) improvement in the bass range (50–700 Hz), which is the most challenging frequency range for radiation enhancement. The adoption of the acoustic metamaterial not only enhances voltage sensitivity near the intrinsic metamaterial resonance frequency, but also extends the broadband enhancement to a lower transducer resonance frequency by carefully engineering the metamaterial‐transducer resonant coupling. The improvement of the audio module is demonstrated through fully coupled electrical‐mechanical‐acoustical numerical simulations using finite element analysis, which are validated against comprehensive measurements including electrical impedance analysis, speaker diaphragm displacement analysis, voltage sensitivity and power sensitivity analysis, and spectrogram. This study not only offers a promising path to improve the audio module quality without increasing the size, but also represents an important milestone toward using acoustic metamaterial research to solve audio industry challenges.

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“…Full control of the phase change along the metasurface requires a very dense array of fine elements. Furthermore, the complex and fine internal geometries of these structures are hard to scale down to higher frequencies, and could induce significant losses in the acoustic thermal and viscous boundary layers near the walls of the structure (25,26). This typical gradient metasurface approach suffers from higher order effects due to the impedance mismatch between incident and scattered waves for large steering angles (13,27), which results in low focusing efficiency for lenses with large numerical aperture (28).…”

Section: Introductionmentioning

confidence: 99%

Scalable Metagrating for Efficient Ultrasonic Focusing

Chiang

Peng

et al. 2021

Phys. Rev. Applied

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Acoustic focusing plays a pivotal role in a wide variety of applications ranging from medical science to nondestructive testing. Previous works have shown that acoustic metagratings can overcome the inherent efficiency limitations of gradient metasurfaces in beam steering. In this work, we propose a new design principle for acoustic metalenses, based on metagratings, to achieve efficient ultrasonic focusing. We achieve beam focusing by locally controlling the excitation of a single diffraction order with the use of adiabatically varying metagratings over the lens aperture. A set of metagratings is optimized by a semi-analytical approach using a genetic algorithm, enabling efficient anomalous reflection for a wide range of reflection angles.Numerical results reveal that our metalens can effectively focus impinging ultrasonic waves to a focal point of FWHM = 0.364λ. The focusing performance of the metalens is demonstrated experimentally, validating our proposed approach.

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Enhanced Low‐Frequency Monopole and Dipole Acoustic Antennas Based on a Subwavelength Bianisotropic Structure

Abstract: BHMR sample and verify the enhanced monopole and dipole acoustic antennas experimentally.

Cited by 11 publications

References 34 publications

Control of the emission of elementary quantum systems using metamaterials and nanometaparticles

Control of the emission of elementary quantum systems using metamaterials and nanometaparticles

Metamaterial‐Augmented Head‐Mounted Audio Module

Scalable Metagrating for Efficient Ultrasonic Focusing

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