Multilevel Plane Wave Based Near-Field Far-Field Transformation for Electrically Large Antennas in Free-Space or Above Material Halfspace
Multilevel Plane Wave Based Near-Field Far-Field Transformation for Electrically Large Antennas in Free-Space or Above Material Halfspace
复制标题
自由空间或材料半空间以上电大天线的基于多级平面波的近场远场变换
DOI：
--
复制
发表时间：
2009
影响因子：
5.7
通讯作者：
T. Eibert
中科院分区：
文献类型：
--
作者：
C. Schmidt;T. Eibert
最近提出的完全探头校正的近场远场变换采用平面波展开和对角平移算子，使近场远场变换为任意测量轮廓和任意天线。多层扩展，灵感来自多层快速多极子方法，提出了一种适用于具有数十个甚至数百个波长的尺寸的电大尺寸天线的有效变换。测量点以多级方式分组，并且仅在最高级别上执行到框中心的平移。平面波的处理通过不同的水平的测量点使用分解和插值程序，从而降低了整体的复杂性。在本文的第二部分中，理想导电地平面和介质半空间的影响，作为一个近似的地面效应在真实的测量设置，进行了研究。因此，假设地面反射波，其从所研究的天线传播到场探头并添加到直接波贡献。这些假设所需的远场条件是通过源盒分组方案来实现的。通过这种扩展，地面效应被直接考虑在近场远场变换。使用模拟和测量的近场数据的转换结果。
A recently presented fully probe-corrected near-field far-field transformation employing plane wave expansion and diagonal translation operators enables near-field far-field transformation for arbitrary measurement contours and arbitrary antennas. A multilevel extension, inspired by the multilevel fast multipole method, is presented that is suitable for the efficient transformation of electrically large antennas with a size of tens or even hundreds of wavelengths. The measurement points are grouped in a multilevel fashion and translations are carried out to the box centers on the highest level only. The plane waves are processed through the different levels to the measurement points using a disaggregation and anterpolation procedure resulting in a reduced overall complexity. In the second part of this paper, the influence of perfectly conducting ground planes and dielectric halfspaces, as an approximation for ground effects in a real measurement setup, is investigated. As such ground reflected waves are assumed, which propagate from the investigated antenna to the field probe and add to the direct wave contributions. The far-field conditions required for these assumptions are achieved by a source box grouping scheme. By this extension ground effects are directly considered within the near-field far-field transformation. Transformation results using simulated and measured near-field data are shown.