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.

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 Near-Field/Far-Field Transformation with Helicoidal Scanning from Irregularly Spaced Data

2010 ◽  
Vol 2010 ◽  
pp. 1-8 ◽  
Author(s):  
Francesco D'Agostino ◽  
Flaminio Ferrara ◽  
Claudio Gennarelli ◽  
Rocco Guerriero ◽  
Massimo Migliozzi
Keyword(s):  
Field Data ◽  
Iterative Scheme ◽  
Near Field ◽  
Optimal Sampling ◽  
Far Field ◽  
Interpolation Algorithm ◽  
Random Errors ◽  
Numerical Tests ◽  
Positioning Errors ◽  
Field Transformation

A fast and accurate technique for the compensation of the probe positioning errors in the near-field/far-field transformation with helicoidal scanning is proposed in this paper. It relies on a nonredundant sampling representation using a spherical modelling of the antenna under test and employs an iterative scheme to evaluate the near-field data at the points fixed by the helicoidal nonredundant representation from the acquired irregularly distributed ones. Once these helicoidal data have been recovered, those required by a classical cylindrical near-field/far-field transformation are efficiently determined by using an optimal sampling interpolation algorithm. Some numerical tests assessing the effectiveness of the proposed approach and its stability with respect to random errors affecting the near-field data are shown.

From Near-Field to Far-Field Coupling in the Third Dimension: Retarded Interaction of Particle Plasmons

Nano Letters ◽  
2011 ◽  
Vol 11 (10) ◽  
pp. 4421-4424 ◽  
Author(s):  
Richard Taubert ◽  
Ralf Ameling ◽  
Thomas Weiss ◽  
André Christ ◽  
Harald Giessen
Keyword(s):  
Near Field ◽  
Far Field ◽  
Field Coupling ◽  
The Third ◽  
Third Dimension

Nonredundant Representation of the Electromagnetic Fields Over a Cylinder with Application to the Near-Field Far-Field Transformation

1996 ◽  
Vol 16 (3) ◽  
pp. 273-290 ◽  
Author(s):  
Ovidio M. Bucci ◽  
Claudio Gennarelli ◽  
Giovanni Riccio ◽  
Vito Speranza ◽  
Catello Savarese
Keyword(s):  
Electromagnetic Fields ◽  
Near Field ◽  
Far Field ◽  
Field Transformation

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 An Innovative Direct NF-FF Transformation Technique with Helicoidal Scanning

2012 ◽  
Vol 2012 ◽  
pp. 1-9 ◽  
Author(s):  
Francesco D’Agostino ◽  
Flaminio Ferrara ◽  
Claudio Gennarelli ◽  
Rocco Guerriero ◽  
Massimo Migliozzi
Keyword(s):  
Electromagnetic Fields ◽  
Field Data ◽  
Near Field ◽  
Transverse Dimension ◽  
Computational Effort ◽  
Far Field ◽  
Transformation Technique ◽  
Spherical Antenna ◽  
Field Transformation ◽  
Mechanical Scanning

A direct near-field-far-field transformation with helicoidal scanning is developed. It is based on the nonredundant sampling representation of electromagnetic fields and uses a spherical antenna modelling to determine the number of helix turns. Moreover, the number of voltage samples on each of them is fixed by the maximum transverse dimension of the antenna, both to simplify the mechanical scanning and to reduce the computational effort. This technique allows the evaluation of the antenna far field directly from a minimum set of near-field data without interpolating them. Although the number of near-field data employed by the developed technique is slightly increased with respect to that required by rigorously applying the nonredundant sampling representation on the helix, it is still remarkably smaller than that needed by the standard near-field-far-field transformation with cylindrical scanning. The effectiveness of the technique is assessed by numerical and experimental results.

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.

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