Investigation on planar near-to-far-field transformations for EMC applications

A comparative analysis of two planar near-field (NF) to far-field (FF) computation methods is proposed. The first method is based on the plane wave spectrum (PWS). The other method is the Planar Scanning Area Extrapolation Method (PSAEM). This method is based on the introduction of auxiliary dipoles mimicking the radiation of a real source in the plane outside the scan area. The accuracy of both methods was tested with EM radiation from a set of elementary electric dipoles radiating at 1GHz and the radiation of a planar textile antenna at 2.5 GHz. Comparisons of NF cartographies at different test planes above the source plane with the reference data were made. It was shown that the PWS method presents an error vector magnitude increasing with the distance between the observation plane and the source plane position. Moreover, the PWS method is also sensitive to the physical size of the scanned data cartographies.