scholarly journals Experimental Testing of Nonredundant Near-Field to Far-Field Transformations with Spherical Scanning Using Flexible Modellings for Nonvolumetric Antennas

2013 ◽  
Vol 2013 ◽  
pp. 1-10 ◽  
Author(s):  
Francesco D'Agostino ◽  
Flaminio Ferrara ◽  
Claudio Gennarelli ◽  
Rocco Guerriero ◽  
Massimo Migliozzi
Keyword(s):  
Experimental Testing ◽  
Near Field ◽  
Experimental Tests ◽  
Two Dimensions ◽  
Far Field ◽  
Time Saving ◽  
Aperture Diameter ◽  
Rotational Surface ◽  
Minimum Number ◽  
The University

This paper deals with the experimental testing of effective probe compensated near-field-far-field (NF-FF) transformations with spherical scanning requiring a minimum number of NF data. They rely on nonredundant sampling representations of the voltage measured by the probe, based on very flexible source modellings suitable for nonvolumetric antennas characterized by two dimensions very different from the other one. In particular, a cylinder ended in two half-spheres is adopted for modelling long antennas, whereas the quasi-planar ones are considered as enclosed in a rotational surface formed by two circular “bowls” having the same aperture diameter, but eventually different bending radii. The NF data needed to perform the classical spherical NF-FF transformation are then accurately and efficiently retrieved from the acquired nonredundant ones via optimal sampling interpolation formulas. A remarkable reduction of the number of the required NF data and, as a consequence, a significant measurement time saving can be so obtained. The experimental tests have been carried out at Antenna Characterization Lab of the University of Salerno and both the NF and FF reconstructions are resulted to be very good, thus confirming the accuracy and reliability of these NF-FF transformations from the experimental viewpoint too.

scholarly journals Effective Antenna Modellings for NF-FF Transformations with Spherical Scanning Using the Minimum Number of Data

2011 ◽  
Vol 2011 ◽  
pp. 1-11 ◽  
Author(s):  
Francesco D'Agostino ◽  
Flaminio Ferrara ◽  
Claudio Gennarelli ◽  
Rocco Guerriero ◽  
Massimo Migliozzi
Keyword(s):  
Electromagnetic Fields ◽  
Near Field ◽  
Two Dimensions ◽  
Geometric Parameters ◽  
Optimal Sampling ◽  
Far Field ◽  
Aperture Diameter ◽  
The Third ◽  
Numerical Tests ◽  
Minimum Number

Two efficient probe-compensated near-field-far-field transformations with spherical scanning for antennas having two dimensions very different from the third one are here developed. They rely on the nonredundant sampling representations of the electromagnetic fields and on the optimal sampling interpolation expansions, and use effective antenna modellings. In particular, an antenna with a predominant dimension is no longer considered as enclosed in a sphere but in a cylinder ended in two half spheres, whereas a surface formed by two circular “bowls” with the same aperture diameter but different lateral bends is adopted to shape an antenna with two predominant dimensions. These modellings are able to fit very well a lot of antennas by properly setting their geometric parameters. It is so possible to remarkably lower the number of data to be acquired, thus significantly reducing the measurement time. Numerical tests assessing the accuracy and the robustness of the techniques are reported.

Experimental Testing on an Effective Technique to Reconstruct the Far- Field Pattern of a Long Antenna from Near-Field Measurements Acquired via Spherical Spiral Scan

2014 ◽  
Vol 8 (1) ◽  
pp. 1-9 ◽  
Author(s):  
F. D’Agostino ◽  
F. Ferrara ◽  
C. Gennarelli ◽  
R. Guerriero ◽  
M. Migliozzi
Keyword(s):  
Experimental Testing ◽  
Near Field ◽  
Field Measurements ◽  
Field Pattern ◽  
Far Field ◽  
Positioning Systems ◽  
Spiral Scanning ◽  
The University ◽  
Far Field Pattern ◽  
Spiral Scan

In this paper, the experimental validation of a fast and accurate near-field – far-field (NF–FF) transformation with spherical spiral scanning for elongated antennas is provided. Such a transformation relies on a nonredundant sampling representation of the voltage measured by the probe, obtained by using the unified theory of spiral scans for nonspherical antennas and adopting a cylinder ended in two half-spheres to model long antennas. It allows a remarkable reduction of the measurement time due to the use of continuous and synchronized movements of the positioning systems and to the reduced number of needed NF measurements. In fact, the NF data required by the classical spherical NF–FF transformation are efficiently and accurately recovered from those collected along the spiral, by using an optimal sampling interpolation expansion. Experimental results, obtained at the Antenna Characterization Lab of the University of Salerno and assessing the effectiveness of such a NF–FF transformation, are shown.

scholarly journals Far-Field Pattern Reconstruction from Near-Field Data Collected via a Nonconventional Plane-Rectangular Scanning: Experimental Testing

2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
Francesco D’Agostino ◽  
Ilaria De Colibus ◽  
Flaminio Ferrara ◽  
Claudio Gennarelli ◽  
Rocco Guerriero ◽  
...  
Keyword(s):  
Experimental Testing ◽  
Near Field ◽  
Interpolation Formula ◽  
Field Pattern ◽  
Far Field ◽  
Planar Antennas ◽  
Aperture Diameter ◽  
Measurement Plane ◽  
Time Required ◽  
Far Field Pattern

This paper deals with the experimental validation of an efficient near-field-far-field (NF-FF) transformation using the planar wide-mesh scanning (PWMS). Such a nonconventional plane-rectangular scanning technique is so named, since the sample grid is characterized by meshes wider and wider when going away from the center, and makes it possible to lower the number of needed measurements, as well as the time required for the data acquisition when dealing with quasi-planar antennas. It relies on the use of the nonredundant sampling representations of electromagnetic fields which employ an oblate ellipsoid or a surface formed by two circular “bowls” with the same aperture diameter but eventually different bending radii to shape a quasi-planar antenna. A two-dimensional optimal sampling interpolation formula allows the reconstruction of the NF data at any point on the measurement plane and, in particular, at those required by the classical NF-FF transformation with the conventional plane-rectangular scanning. The measurements, performed at the planar NF facility of the antenna characterization laboratories of Selex ES, have confirmed the effectiveness of this innovative scanning also from the experimental viewpoint.

scholarly journals Near-Field to Far-Field Transformation Techniques with Spiral Scannings: A Comprehensive Review

2014 ◽  
Vol 2014 ◽  
pp. 1-13 ◽  
Author(s):  
Renato Cicchetti ◽  
Francesco D’Agostino ◽  
Flaminio Ferrara ◽  
Claudio Gennarelli ◽  
Rocco Guerriero ◽  
...  
Keyword(s):  
Communication Systems ◽  
Near Field ◽  
Theoretical Background ◽  
Wireless Communication Systems ◽  
Far Field ◽  
Unified Theory ◽  
Transformation Techniques ◽  
Positioning Systems ◽  
Rotational Surface ◽  
Spiral Scanning

An overview of the near-field-far-field (NF-FF) transformation techniques with innovative spiral scannings, useful to derive the radiation patterns of the antennas commonly employed in the modern wireless communication systems, is provided in this paper. The theoretical background and the development of a unified theory of the spiral scannings for quasi-spherical and nonspherical antennas are described, and an optimal sampling interpolation expansion to evaluate the probe response on a quite arbitrary rotational surface from a nonredundant number of its samples, collected along a proper spiral wrapping it, is presented. This unified theory can be applied to spirals wrapping the conventional scanning surfaces and makes it possible to accurately reconstruct the NF data required by the NF-FF transformation employing the corresponding classical scanning. A remarkable reduction of the measurement time is so achieved, due to the use of continuous and synchronized movements of the positioning systems and to the reduced number of needed NF measurements. Some numerical and experimental results relevant to the spherical spiral scanning case when dealing with quasi-planar and electrically long antennas are shown.

Far-field pattern reconstruction directly from a minimum number of helicoidal near-field data

2012 ◽  
Author(s):  
Francesco D'Agostino ◽  
Flaminio Ferrara ◽  
Claudio Gennarelli ◽  
Rocco Guerriero ◽  
Massimo Migliozzi
Keyword(s):  
Field Data ◽  
Near Field ◽  
Field Pattern ◽  
Far Field ◽  
Minimum Number ◽  
Pattern Reconstruction ◽  
Far Field Pattern

scholarly journals Non-redundant Spherical Near-Field to Far-Field Transformation for a Volumetric Antenna in Offset Configuration

2019 ◽  
Vol 13 (1) ◽  
pp. 19-29 ◽  
Author(s):  
Francesco D’Agostino ◽  
Flaminio Ferrara ◽  
Claudio Gennarelli ◽  
Rocco Guerriero ◽  
Massimo Migliozzi
Keyword(s):  
Near Field ◽  
Measurement Techniques ◽  
Data Gathering ◽  
Experimental Tests ◽  
Precise Determination ◽  
Far Field ◽  
Interpolation Algorithm ◽  
Classical Technique ◽  
Field Transformation

Background: 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. Objective: 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. Methods: 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. Conclusion: The numerical simulations and experimental tests demonstrate the effectiveness of the developed approach accounting for an offset mounting of the AUT.

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