An Effective Method for Improving the Scanning Plane Accuracy of a Planar Near-Field Scanner System

This paper presents an effective method for improving the accuracy of planar scanning for a special moveable near-field Scanner system, which is use to measure beam patterns in a large antenna array. Using a tracking laser interferometer, error correction maps are constructed for the X-, Y- and Z-axes to compensate for the alignment of the scanning plane of a planar near-field scanner system. The test results confirm that the error correction map compensation method substantially improves the plane-scanning accuracy for position alignment and near field measurement results.The planar accuracy was improved using an error compensation table. The Z-axis error of the scanned plane without compensated is +0.3 /-0.15 mm and the RMS error is 0.082mm. The Z-axis error with compensation plane is -0.01/-0.02 mm and the RMS planarity is 0.004 mm. The laser tracker provides a higher degree of accuracy and saves time on position alignment.