What is the coordinate system reference for far-field radiation patterns obtained on a PNF range? Also, what is the ref plane when doing a back projection?
The probe reference when located at the scanner (x,y,z) = (0,0,0) point is the coordinate reference. The reference point on the probe is the origin of the probe coordinate system that is used to measure or calculate the amplitude and phase pattern of the probe. When using measured probe pattern files, the calibration laboratory should have defined the location of the probe coordinate system. For an OEWG this is normally defined to be in the plane defined by the open end of the probe with the X-Y axes parallel to the side walls of the probe and the Z-Azis centered on the probe parallel to the long dimension of the probe. It could be defined differently, and in such cases the probe’s phase patterns would change but the probe corrected AUT pattern should be independent of the definition of the probe’s coordinates for a measured probe pattern. Any change in the X, Y or Z location of the probe origin will produce a change in the measured probe pattern that will be equal in magnitude and opp
