A new and efficient NF-FF transformation with spherical spiral scanning
A new and efficient NF-FF transformation with spherical spiral scanning
复制标题
一种新型高效的球面螺旋扫描 NF-FF 变换
DOI：
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发表时间：
2001
期刊：
影响因子：
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通讯作者：
C. Savarese
中科院分区：
文献类型：
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作者：
O. Bucci;C. Gennarelli;F. D’Agostino;C. Savarese
天线近场（NF）设施，以克服这些缺点，这使得它不切实际的测量在传统的远场（FF）范围内的电大天线。在NF-FF变换技术中，采用球面扫描是特别有趣的，因为它给出了完整的天线方向图覆盖。这项工作的目的是确定天线的FF模式从NF测量的螺旋包裹一个球体从极点到极点与一个恒定的步骤/spl θ/。通过考虑一个理想的探头，一个方便的方法来做到这一点是开发一个有效的插值算法的电磁（EM）场重建的领域从知识的非冗余数量的样本所考虑的螺旋。这允许确定具有球面扫描的NF-FF变换技术所需的NF数据。出发点已表示的发展的非冗余采样表示的领域的螺旋线，根据有关的分析性质的领域的分析结果，封闭在一个凸域与旋转对称的有限大小的源辐射，并观察到在一个表面上具有相同的对称性。然后，螺旋的步长被选择为与Bucci（1991）的方法所需的样本间隔一致，以沿子午线沿着内插场，从而允许开发所需的二维内插公式。这种公式的准确性和稳定性以及所提出的创新NF-FF变换技术的有效性已经通过许多数值模拟进行了评估。
Antenna near-field (NF) facilities are employed to overcome those drawbacks which, for electrically large antennas, make it impractical to measure antenna patterns on a conventional far-field (FF) range. Among the NF-FF transformation techniques, employing spherical scanning is particularly interesting since it gives the full antenna pattern coverage. The aim of this work is to determine the antenna FF pattern from NF measurements made over a spiral wrapping a sphere from pole to pole with a constant step in /spl theta/. By considering an ideal probe, a convenient way to do this is to develop an efficient interpolation algorithm for the electromagnetic (EM) field reconstruction over the sphere from knowledge of the nonredundant number of samples over the considered spiral. This allows one to determine the NF data required by the NF-FF transformation technique with spherical scanning. The starting point has been represented by the development of a non-redundant sampling representation of the field over the spiral, based on theoretical results concerning the analytical properties of the fields radiated by finite size sources enclosed in a convex domain with rotational symmetry and observed over a surface having the same symmetry. Then, the step of the spiral has been chosen coincident with the sample spacing needed by the approach of Bucci (1991) to interpolate the field along a meridian, thus allowing one to develop the required two-dimensional interpolation formula. The accuracy and stability of such a formula and the effectiveness of the proposed innovative NF-FF transformation technique have been assessed by many numerical simulations.