Since the measurement time is a critical factor the IHF ivenstigates how the measurement time can be reduced by alternative sampling methods. The plane wave spectrum is circular and thus a rectangular grid is not optimal, so the implementation of a hexagonal sampling is examined. Furthermore, other methods like plane-polar sampling are investigated, which have benefits for special antennas and applications.
In planar near-field measurements the radiated field is measured on a flat rectangular surface in front of an antenna (AUT). This geometry allows a simple and inexpensive mechanical setup. Moreover, the transformations are mathematically simple to describe and easy to implement. First a plane wave spectrum (PWS) is calculated from the measurement data and then projected into the far-field. However, this measurement setup provides only a small reliable angular range in the far-field because the measurement surface is limited (truncation effect). Therefore, the planar near-field is mainly used for the measurement of directive antennas.