Reduction of Truncation Errors in Spherical Near-Field Antenna Measurements Using Gerchberg-Papoulis Algorithm

The truncated spherical near-field (SNF) measurement is widely employed in antenna testing. Nevertheless, the truncation error resulting from the truncated measurement surface inevitably compromises the measurement precision. In this paper, a SNF measurement truncation error reduction methodology based on the Gerchberg-Papoulis algorithm is introduced. By iteratively applying constraints in both the spatial and spectral domains, the unmeasured near-field data is effectively extrapolated. Two numerical results are provided to demonstrate that the presented methodology significantly enhances the accuracy of the reconstructed far-field pattern. Furthermore, comparisons with conventional methods, including zero-padding and last value extrapolation, are provided to highlight the effectiveness and robustness of the presented methodology.