Improving the Directionality of Low-Frequency Acoustic Radiation by a Finite Array of Quadrupolar Sources with Acoustic Metamaterials
Qinglei Zeng,
Shenlian Gao,
Yun Lai,
Xiaozhou Liu
Affiliations
Qinglei Zeng
Key Laboratory of Modern Acoustics, Institute of Acoustics and School of Physics, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, China
Shenlian Gao
Key Laboratory of Modern Acoustics, Institute of Acoustics and School of Physics, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, China
Yun Lai
Key Laboratory of Modern Acoustics, Institute of Acoustics and School of Physics, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, China
Xiaozhou Liu
Key Laboratory of Modern Acoustics, Institute of Acoustics and School of Physics, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, China
Manipulating radiation patterns is challenging, especially at low frequencies. In this paper, we demonstrate that acoustic metamaterials arranged as an array of quadrupoles remarkably improve the directionality of acoustic radiation at low frequencies, compared with previous metamaterials arranged as monopole and dipole structures. The directivity of the acoustic radiation can be adjusted by changing the characteristic parameter and the symmetry of the structure, which provides a flexible method of adjusting radiation directions. The directionality can be further improved by constructing a linear array. Our work establishes acoustic radiation control via quadrupolar metamaterials.
