Spherical near-field alignment sensitivity for polar and equatorial antenna measurements

摘要

Spherical near-field (SNF) antenna test systems offer unique advantages over other types of measurement configurations and have become increasingly popular as a result. To yield accurate far-field radiation patterns, it is critical that the rotators of the SNF scanner are properly aligned. Many techniques using optical instruments, laser trackers, low cost devices or even electrical measurements have been developed to align these systems. While these alignment procedures have been used in practice with great success, some residual alignment errors always remain. This paper expands on prior work by analyzing the effects of spherical alignment errors for a variety of different measurement grids on a theta-over-phi SNF scanner. Results are presented using a combination of physical alignment perturbations (measured) and errors induced via simulation. A variety of antenna types and directions of radiation within the measurement sphere are considered.