Highly Efficient Near-Field to Far-Field Transform for Polar Near-Field Scanned Data

Despite being a comparatively uncommonly encountered near-field antenna measurement configuration, plane-polar systems are important as they present certain distinctive and very attractive attributes. These include mechanical simplicity and the ability to acquire near-field data across acquisition intervals that are potentially far larger than the measurement system itself or the test chamber in which it is situated. They do however require specialist near-field to far-field data transformation algorithms which can pose implementation challenges in terms of numerical accuracy and computational efficiency. This paper presents a new, efficient, rigorous, data transformation algorithm that can also transform data acquired over rotationally symmetric, non-planar measurement surfaces. The new, accelerated, Fourier-Bessel based transform is verified through numerical simulation and its successful application in transforming measured data of a high gain, passive, space-borne synthetic aperture radar (SAR) antenna is highlighted.