Near-field to far-field transformations constitute a powerful antenna characterization technique for near-field measurement scenarios. In this paper, a near-field to far-field transformation technique based on multiple spherical wave expansions (SWEs) is presented. Thanks to its iterative matrix inversion nature, the approach performs the transformation of fields measured on arbitrary surfaces. Also, irregular sampling schemes can be incorporated. The proposed algorithm is based on modeling the antenna fields with not one, but several SWEs distributed over its geometry. Due to the high number of SWEs, their truncation number can be arbitrarily reduced. Working with expansions of low order allows us to incorporate the probe correction in the transformation in a very simple way, accepting any type of probe and orientation. Only the probe far-field pattern is used, thus working with its full SWE is avoided. The algorithm is validated using simulated field data as well as measurements of real antennas.

中文翻译：

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使用多个球面波展开的探头校正近场到远场变换

近场到远场的转换构成了用于近场测量场景的强大天线表征技术。在本文中，提出了一种基于多个球面波扩展（SWE）的近场到远场转换技术。由于其迭代矩阵求逆性质，该方法执行在任意表面上测量的场的变换。此外，可以合并不规则的采样方案。所提出的算法基于对天线场进行建模，其中不是一个，而是几个分布在其几何形状上的 SWE。由于 SWE 的数量很多，它们的截断数可以任意减少。使用低阶扩展使我们能够以非常简单的方式将探针校正合并到转换中，接受任何类型的探针和方向。仅使用探头远场模式，因此避免了使用其完整的 SWE。该算法使用模拟现场数据以及真实天线的测量结果进行了验证。