论文标题
声学波导中的低频源成像
Low-frequency source imaging in an acoustic waveguide
论文作者
论文摘要
分析了二维波导中的时谐波远场阵列阵列成像。考虑到低频的情况，波导的直径略大于波长，因此波导支持有限数量的引导模式，并且天线阵列的直径小于波长，因此在开放介质中的标准分辨率公式可以预测出非常差的成像分辨率。引入了一个一般框架，用于分析此类天线阵列的分辨率和稳定性性能。结果表明，平面天线阵列的性能（就测量噪声而言，在分辨率和稳定性方面）比线性（水平或垂直）阵列表现更好，并且对于给定的直径，垂直线性阵列的性能优于水平阵列。然而，由于分散关系的形式，发现波导中成像的基本局限性。标量波是固有的，无论介质的复杂性和阵列几何形状的复杂性如何。
Time-harmonic far-field source array imaging in a two-dimensional waveguide is analyzed. A low-frequency situation is considered in which the diameter of the waveguide is slightly larger than the wavelength, so that the waveguide supports a limited number of guided modes, and the diameter of the antenna array is smaller than the wavelength, so that the standard resolution formulas in open media predict very poor imaging resolution. A general framework to analyze the resolution and stability performances of such antenna arrays is introduced. It is shown that planar antenna arrays perform better (in terms of resolution and stability with respect to measurement noise) than linear (horizontal or vertical) arrays and that vertical linear arrays perform better than horizontal arrays, for a given diameter. However a fundamental limitation to imaging in waveguides is identified that is due to the form of the dispersion relation. It is intrinsic to scalar waves, whatever the complexity of the medium and the array geometry.
