Near-field error analysis for arbitrary scanning grids using fast irregular antenna field transformation algorithm

Abstract

An extensive error analysis for arbitrary near-field antenna measurements is performed. Expressions are derived to estimate the far-field uncertainty using the available near-field data together with the measurement inaccuracy but, most importantly, without the knowledge of the reference far field. Error analysis techniques presented so far either assume a specific set of antennas or a specific measurement surface and are difficult to generalize. We present a generalized approach providing realistic error estimates using the recently developed Fast Irregular Antenna Field Transformation Algorithm (FIAFTA). FIAFTA utilizes equivalent plane wave sources to represent radiated antenna fields and is able to process near-field data collected on arbitrary measurement grids. The unknown plane wave coefficients are determined by solving a linear system of equations. The error model is applied to planar, cylindrical, and spherical near-field measurements and is also valid for arbitrary measurement grids. The estimated far-field uncertainties show good agreement with the reference far-field errors.