Applications of Iterative Matrix Inversion in Near to Far Field Transformation Algorithms

Near-field to far-field transformations constitute a powerful antenna characterization technique for antenna measurement. In this paper applications for near-field to far-field transformations are introduced. In all these cases, iterative matrix inversion is used to retrieve the antenna spherical wave expansion, instead of the FFT based classical solution. This technique is more time consuming, but thanks to the development of the computing capabilities their advantages can be exploited, allowing some degrees of freedom in the resolution of the electromagnetic problem. The examples and applications shown in this paper are the following ones: the first technique is a multilevel spherical wave expansion that allows to reduce the processing time and process measurements in irregular grids. The second one is a technique used for reducing the number of measurement points for specific antennas with some symmetries. The third application allows the reduction of measurement samples for offset-mounted antennas, applied to automotive scenarios.