The accurate and highly stable SNIFT software transforms measured spherical near-field antenna data to far fields, accounting for the full characteristics of the measuring probe.
Rotation of the spherical wave coefficients
If only a certain region of the antenna pattern has interest, it is possible to perform truncated measurements and still use SNIFT for the transformation. The transformed data are referred to the measurement coordinate system, but if, for example, the region of interest does not coincide with this system (e.g. a scanned beam), the supplementary program ROSCOE can be applied to do the appropriate coordinate transformation into a system centered around the peak.
Accurate determination of spherical harmonics
Well-founded choice of numerical implementation ensures a very stable algorithm, also for high-order harmonics. Antennas with diameters exceeding several hundred wavelengths are handled within seconds on a standard PC with accurate determination of all involved spherical harmonics.