基于振幅加权的阵列辐射强度分布的理论与数值实验研究

【作者】 种兰祥；

【导师】 张志勇；

【作者基本信息】 中国科学院研究生院（西安光学精密机械研究所） ， 物理电子学， 2012， 博士

【摘要】 相控阵列的研究可以追溯到二十世纪五十年代。但是，相控阵列技术真正被应用于诸如卫星通信、弹道导弹预警、气象雷达、工业无损检测、医学诊断与治疗等领域却是近二十年来的事。最近几年来，随着人类对能源需求的持续增加和对生态环境的日益重视，声波相控阵列又被用于地下资源勘探、地质评价和测井中。在这些应用中，无论是电磁波还是声波，其波束形成、空间扫描都是对阵元辐射相位进行控制，以达到在空间产生特定的辐射模型或进行空间扫描。这就是人们不断研制高精确度的、结构复杂的相位延迟网络和控制系统的原因。然而，人们不断追求高的辐射频率，增加振元数目，使得相位延迟网络和控制系统的制造变得愈来愈困难。而作为波动的另一个独立可控变量振幅却没有给予充分利用。本文研究发现，对阵元辐射振幅进行恰当控制，可实现特定的辐射模型。无论是从原理上还是工程讲，实现对振幅大小的控制比对相位的控制要简单得多。本文首先指出，对阵元辐射振幅控制形成所需的辐射强度分布是可行的。其次，在远场情况下，提出了半波约束条件和波束质量评价标准，用不同的数学方法，导出了远场与近场情况下的振元振幅取值的计算公式。最后通过实例，进行数值分析，证明了所述方法的有效性。本文还指出，如果将振幅加权与线性相位控制联合使用，实现在特定远场辐射振幅分布不变条件下的波束空间电子扫描，这也可以降低阵列相移器和控制器的复杂度与成本。采用振幅加权形成特定的辐射强度分布方法的潜在应用，包括战时通信、医学治疗、特殊形式的无损、非接触探测等。本文的方法可以推广到阵元呈周期性排列的其它阵列结构中。更多还原

【Abstract】 The concept of phased array was first emerged in the research of directional antenna in the late1950s. Phased array technology has been actually used in the fields of satellite communication, aerial reconnaissance and ballistic missile system, radar systems for meteorology, industry nondestructive testing, as well medical diagnosis and noninvasive treatment in recent in the last two decades. Since demand for energy resources and emphasis on ecological environment are on continuous increase in recent years, acoustic phased array has been applied to prospecting for underground resources, geological evaluation, and well logging. The beam forming and scanning in the applications mentioned above depend on the control over the element radiation phases, so as to construct a spatial radiation pattern. These need the support of a delicate phase shifter network and control system with precise and complex structure. The radiation amplitude, which is another controllable quantity of a wave, is not fully utilized. Our study found that a specific radiation pattern can be formed by only weighting the radiation amplitudes of planar array elements. From engineering accomplishment angle, weighting amplitudes is easier than shifting phases.This dissertation first pointed out that is possible to form a specific radiation intensity distribution by controlling the amplitude of radiation emitted by elements. Secondly, half-wave constraint and beam quality evaluation criteria in far field have been put forwarded, and the formula for calculating amplitudes in the case of far-field and near-field have been derived. Finally, a number of instances have been analyzed numerically, and the effectiveness of the method described above has been demonstrated. The potential applications of the method using amplitude-weighted include wartime communication, medical treatment, a special form of non-destructive and non-contact detection etc. This method can be extended to the array in which the element was periodically arranged.更多还原