Near-field-far-field transformation from nonredundant plane-polar data: effective modellings of the source

The paper provides a fast and accurate technique for the far-field evaluation from a nonredundant number of plane-polar near-field samples. By introducing very flexible modellings of the source, which fit very well a lot of actual sources, a new sampling technique is developed to recover the plane-rectangular data from the knowledge of the plane-polar ones. It must be stressed that the amount of required plane-polar data remains finite also when the radius of the scanning zone approaches infinity and it can be significantly lower than the amount needed by using a spherical modelling of the source. This result is based on an appropriate choice of the phase function extracted from the field expression and of the coordinates used to describe the plane and on the reduced volumetrical redundancy of the proposed source modellings. The effectiveness of the proposed technique is proved by numerical examples and its stability is verified by adding randomly distributed errors to the ideal near-field samples