Non-redundant Spherical Near-Field to Far-Field Transformation for a Volumetric Antenna in Offset Configuration
Francesco D’Agostino, Flaminio Ferrara, Claudio Gennarelli*, Rocco Guerriero, Massimo Migliozzi
Department of Industrial Engineering - University of Salerno, Fisciano, Italy
The development of fast Near-Field (NF) measurement techniques allowing the precise determination of the Far-Field (FF) radiation features of an antenna is becoming more and more challenging nowadays.
The goal of the article is the development of an NF To FF Transformation (NFTFFT) with spherical scan for offset mounted volumetric Antennas Under Tests (AUTs) requiring, unlike the classical technique, a reduced set of NF data, that is of the same amount as for the onset mounting case, thus making data gathering faster. In fact, the number of NF data needed by the standard approach may considerably increase in this case, since the size of the smallest sphere surrounding the AUT and centered at the center of the measurement sphere rises.
This goal has been achieved by profitably exploiting the non-redundant sampling representation of electromagnetic field and assuming a volumetric AUT as contained in a sphere. An optimal sampling interpolation algorithm is then employed to precisely reconstruct the input NF data for the traditional spherical NFTFFT from the reduced set of the collected ones.
The numerical simulations and experimental tests demonstrate the effectiveness of the developed approach accounting for an offset mounting of the AUT.
Keywords: Antenna measurements, Non-redundant sampling representations of electromagnetic fields, Spherical scanning, Offset mounting, Near-field to far-field transformations, FF region, EM Field.
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* Address correspondence to this author at the Department of Industrial Engineering - University of Salerno; via Giovanni Paolo II, 132 - 84084 Fisciano (SA) Italy; E-mail: email@example.com