Measuring patch array antennas by an optically modulated scatterer

Two printed patch array antennas, a coplanar corporate fed 8/spl times/8 rectangular patch array at 12 GHz and a 6/spl times/1 circular slot patch array at 5.3 GHz, have been measured by a field mapping system using planar near-field scans with an optically modulated scatterer as the field sensor. The surface scans are made immediately above the patch array structure. They provide a good tool for diagnostic analysis of their working state of the antennas. The scans less than half wavelength above the surface give good results for their radiation patterns, which can be transformed to greater distances.