The bi-polar planar near-field measurement technique. I - Implementation and measurement comparisons. II - Near-field to far-field transformation and holographic imaging methods

The paper presents a novel customized bipolar planar near-field antenna measurement technique as an alternative to the plane-rectangular and plane-polar measurement techniques. The bipolar and near-field scanner incorporates an axially rotating test antenna and a rotating probe-carrying arm to sample the near-field on a data grid consisting of concentric circles and radial arcs. Measured results are compared with those produced by a far-field range and a plane-rectangular planar near-field range to verify the implementation and validate the method. Excellent agreement is obtained for both the copolarized and cross-polarized fields. The data processing algorithms that have been developed and customized to exploit the unique features of the bipolar planar near-field measurement technique are examined. Near-field to far-field transformation algorithms investigated include both interpolatory and noninterpolatory algorithms due to the atypical arrangement of the bipolar near-field samples. (AIAA)