使用相位共轭阵列进行声源定位的相关参数研究

基于相位共轭方法采用离散阵列对用于声源定位的相位共轭阵列参数进行了数值计算研究,研究了阵元间距、阵列面积、声源频率和阵列形式等对声场聚焦幅值和空间尺寸大小的影响.数值计算结果表明:采用平面阵列,为突破声波衍射极限,阵元间距应为△≤0.5λ,最优的阵元间距为0.15λ.在近场基于声压梯度测量使用偶极子源的相位共轭阵列,阵列边长满足a≥1.4λ即可,并且随着频率升高,相位共轭声场的幅值增大,得到的相位共轭分辨率降低.对于阵列形式,采用十字交叉阵列可用较少的阵元个数就可以突破衍射极限.如果阵列与声源为共形面,推导出相位共轭声场幅值与声源的辐射声功率成比例,文中还计算并验证了相位共轭声场幅值与辐射立体角的关系.

Study on the Parameters of Phase Conjugation Arrays for Sound Localization and Identification

The parameters such as element spacing, array area, source frequency, array forms of phase conjugation arrays consisting of discrete elements are studied numerically for sound source localization.The influences of these parameters on the field magnitude and the spatial size of the conjugated field are investigated.The results show that the element spacing should be less than 0.5λ to break the diffraction limit with the planar array only made of dipole transceivers in the near field,the optimal element spacing is 0.15λ and the array side length should be greater than or equal to 1.4λ.With increasing frequency the field magnitude increases and the spatial resolution decreases.Regarding to the number of array elements and the performance the optimal array form is the cross array which leads to subwavelength focusing with fewer elements.If the array and the sound source are the conformal surfaces,the field amplitude is proportional to the sound radiation power.The relationship between the field amplitude and the radiation solid angle are also analyzed.