TIME-DOMAIN CHARACTERISTICS OF DISPERSIVE ACOUSTIC METAMATERIALS
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- 英文论文题名：TIME-DOMAIN CHARACTERISTICS OF DISPERSIVE ACOUSTIC METAMATERIALS
- 论文作者：Zhao-jun WANG ; Hong-kuan ZHANG ; Xiao-ming ZHOU
- 英文论文作者：Zhao-jun WANG ; Hong-kuan ZHANG ; Xiao-ming ZHOU ; Key Laboratory of Dynamics and Control of Flight Vehicle ; Ministry of Education ; School of Aerospace Engineering ; Beijing Institute of Technology
- 年：2016
- 作者机构：Key Laboratory of Dynamics and Control of Flight Vehicle, Ministry of Education, School of Aerospace Engineering, Beijing Institute of Technology;
- 英文论文关键词：Acoustic metamaterial ; Dispersive FDTD ; Negative refraction
- 会议召开时间：2016-10-21
- 会议录名称：2016年全国压电和声波理论及器件应用研讨会论文摘要集
- 英文会议录名称：Abstract Book of 2016 Symposium on Piezoelectricity, Acoustic Waves and Device Applications
- 语种：英文
- 分类号：TB34
- 学会代码：AGLU
- 会议名称：2016年全国压电和声波理论及器件应用研讨会
- 会议地点：中国陕西西安
- 主办单位：中国力学学会、中国声学学会、IEEE UFFC分会
- 学会名称：中国力学学会
- 页数：2
- 文件大小：9k
- 原文格式：D
- 会议级别：全国
摘要
Background, Motivation and Objective In a general case, linear acoustic equation involves a tensor mass and a scalar compressibility. This equation can be used to describe the wave behavior of acoustic metamaterials, for which partial or full components of the density tensor, or the compressibility can be negative due to wave dispersion. The novel physical properties adhered to metamaterials stem from their peculiar artificial microstructures. For instance, negative mass can be obtained through the dipolar resonance of the man-made micro structures; negative compressibility comes from the monopole resonance. Except bringing the novel dynamic properties, the resonance results in the non-trivial dispersion characteristics of the effective medium models. This brings a big difference of wave responses between the pulse loading and steady-state excitation. This work makes a complete study of time-domain properties of dispersive acoustic metamaterials. Statement of Contribution/Methods We develop the dispersive finite-difference time-domain(FDTD) simulation algorithms for a general acoustic equation, where the mass components and compressibility can be of either Drude or Lorentz dispersion models. The program has been used to verify negative refraction and wave focusing by a planar metamaterial slab with double negativity. Results Wave propagation characteristics in acoustic metamaterials with all admissible material parameters are analyzed. Negative refraction phenomena have been found in three different dispersion regimes, and verified by the time-domain simulation using acoustic pulse beam as the excitation. It is found that the envelope orientation of the beam, and its phase and group velocity direction in the refracted medium can be mutually different. We also study acoustic characteristics of a conjugate pair that permits wave propagation at only the cutoff wavenumber. Due to the inherent dispersion of the pair, the cutoff point varies monotonically with the frequency. As demonstrated by the FDTD simulation, these features make the conjugate pair like an acoustic radiation device capable of modulating the radiation angle with the source frequency. Discussion and Conclusions The developed numerical simulator based on the FDTD has been demonstrated as a powerful tool to study the transient behavior of dispersive metamaterials. With the help of this dispersive FDTD simulator, the metamaterial application under transient wave environment in practical engineering can be deeply explored.
Background, Motivation and Objective In a general case, linear acoustic equation involves a tensor mass and a scalar compressibility. This equation can be used to describe the wave behavior of acoustic metamaterials, for which partial or full components of the density tensor, or the compressibility can be negative due to wave dispersion. The novel physical properties adhered to metamaterials stem from their peculiar artificial microstructures. For instance, negative mass can be obtained through the dipolar resonance of the man-made micro structures; negative compressibility comes from the monopole resonance. Except bringing the novel dynamic properties, the resonance results in the non-trivial dispersion characteristics of the effective medium models. This brings a big difference of wave responses between the pulse loading and steady-state excitation. This work makes a complete study of time-domain properties of dispersive acoustic metamaterials. Statement of Contribution/Methods We develop the dispersive finite-difference time-domain(FDTD) simulation algorithms for a general acoustic equation, where the mass components and compressibility can be of either Drude or Lorentz dispersion models. The program has been used to verify negative refraction and wave focusing by a planar metamaterial slab with double negativity. Results Wave propagation characteristics in acoustic metamaterials with all admissible material parameters are analyzed. Negative refraction phenomena have been found in three different dispersion regimes, and verified by the time-domain simulation using acoustic pulse beam as the excitation. It is found that the envelope orientation of the beam, and its phase and group velocity direction in the refracted medium can be mutually different. We also study acoustic characteristics of a conjugate pair that permits wave propagation at only the cutoff wavenumber. Due to the inherent dispersion of the pair, the cutoff point varies monotonically with the frequency. As demonstrated by the FDTD simulation, these features make the conjugate pair like an acoustic radiation device capable of modulating the radiation angle with the source frequency. Discussion and Conclusions The developed numerical simulator based on the FDTD has been demonstrated as a powerful tool to study the transient behavior of dispersive metamaterials. With the help of this dispersive FDTD simulator, the metamaterial application under transient wave environment in practical engineering can be deeply explored.
Background, Motivation and Objective In a general case, linear acoustic equation involves a tensor mass and a scalar compressibility. This equation can be used to describe the wave behavior of acoustic metamaterials, for which partial or full components of the density tensor, or the compressibility can be negative due to wave dispersion. The novel physical properties adhered to metamaterials stem from their peculiar artificial microstructures. For instance, negative mass can be obtained through the dipolar resonance of the man-made micro structures; negative compressibility comes from the monopole resonance. Except bringing the novel dynamic properties, the resonance results in the non-trivial dispersion characteristics of the effective medium models. This brings a big difference of wave responses between the pulse loading and steady-state excitation. This work makes a complete study of time-domain properties of dispersive acoustic metamaterials. Statement of Contribution/Methods We develop the dispersive finite-difference time-domain(FDTD) simulation algorithms for a general acoustic equation, where the mass components and compressibility can be of either Drude or Lorentz dispersion models. The program has been used to verify negative refraction and wave focusing by a planar metamaterial slab with double negativity. Results Wave propagation characteristics in acoustic metamaterials with all admissible material parameters are analyzed. Negative refraction phenomena have been found in three different dispersion regimes, and verified by the time-domain simulation using acoustic pulse beam as the excitation. It is found that the envelope orientation of the beam, and its phase and group velocity direction in the refracted medium can be mutually different. We also study acoustic characteristics of a conjugate pair that permits wave propagation at only the cutoff wavenumber. Due to the inherent dispersion of the pair, the cutoff point varies monotonically with the frequency. As demonstrated by the FDTD simulation, these features make the conjugate pair like an acoustic radiation device capable of modulating the radiation angle with the source frequency. Discussion and Conclusions The developed numerical simulator based on the FDTD has been demonstrated as a powerful tool to study the transient behavior of dispersive metamaterials. With the help of this dispersive FDTD simulator, the metamaterial application under transient wave environment in practical engineering can be deeply explored.
引文