Improving the Calibration Efficiency of an Array Fed Reflector Antenna Through Constrained Beamforming
Improving the Calibration Efficiency of an Array Fed Reflector Antenna Through Constrained Beamforming
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DOI：
10.1109/tap.2013.2255577
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发表时间：
2013-03
影响因子：
5.7
通讯作者：
A. Young;M. Ivashina;R. Maaskant;O. Iupikov;D. Davidson
中科院分区：
文献类型：
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作者：
A. Young;M. Ivashina;R. Maaskant;O. Iupikov;D. Davidson
基于多波束相控阵馈电 (PAF) 的射电望远镜的辐射方向图校准很大程度上取决于方向图模型的准确性，以及是否有合适的参考源来求解方向图模型中的未知参数。展示了如何通过使用线性约束最小方差 (LCMV) 波束形成器使波束形成的远场方向图符合基于物理的两参数分析参考模型，从而提高 PAF 天线方向图校准的效率。通过这种方法，只需要几次校准测量，就可以获得准确且简单的图案模型。研究了模型参数对多个扫描波束的方向性和旁瓣电平的影响，并将这些结果用于所提出的 MeerKAT 天线的 PAF 波束形成器设计示例中。与通常使用的最大方向性（MaxDir）波束形成器相比，所提出的约束波束形成方法能够在宽视场（FoV）上产生波束图案，并以更高的精度进行建模，并显着降低图案校准复杂性。
Calibrating for the radiation pattern of a multi-beam Phased array feed (PAF) based radio telescope largely depends on the accuracy of the pattern model, and the availability of suitable reference sources to solve for the unknown parameters in the pattern model. It is shown how the efficiency of this pattern calibration for PAF antennas can be improved by conforming the beamformed far field patterns to a two-parameter physics-based analytic reference model through the use of a linearly constrained minimum variance (LCMV) beamformer. Through this approach, which requires only a few calibration measurements, an accurate and simple pattern model is obtained. The effects of the model parameters on the directivity and sidelobe levels of multiple scanned beams are investigated, and these results are used in an example PAF beamformer design for the proposed MeerKAT antenna. Compared to a typically used maximum directivity (MaxDir) beamformer, the proposed constrained beamforming method is able to produce beam patterns over a wide Field-of-View (FoV) that are modeled with a higher degree of accuracy and result in a significant reduction in pattern calibration complexity.