An Effective NF-FF Transformation Technique With Planar Spiral Scanning Tailored For Quasi-Planar Antennas

D’Agostino, Francesco; Ferrara, Flaminio; Gennarelli, Claudio; Guerriero, Rocco

doi:10.1109/tap.2008.928786

Cited by 40 publications

(50 citation statements)

References 12 publications

(33 reference statements)

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“…Planar, cylindrical, or spherical surfaces are the most common acquisition surfaces, with recent extensions to arbitrary geometry [9] or noncanonical domains [10,11]. The acquired NF can be employed to obtain the FF radiation pattern of the antenna by means of mathematical NF-FF transformations based either in wave expansions [1,12,13] or integral equation methods such as the sources reconstruction method (SRM) [3,9].…”

Section: Introductionmentioning

confidence: 99%

Indirect Off-Axis Holography for Antenna Metrology

Arboleya

Laviada

Ala‐Laurinaho³

et al. 2017

Holographic Materials and Optical Systems

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Phase acquisition in antenna measurement, especially at millimeter-and submillimeterwave frequencies, is an expensive and challenging task. The need of a steady phase reference demands not only a very stable source but unvarying temperature conditions and strong positioning accuracy requirements. Indirect off-axis holography is an interferometric technique that allows for characterization of an unknown field by means of a simple filtering process of the hologram or intensity interference pattern in the spectral domain, provided that the reference field, employed to interfere with the unknown field, is known in amplitude and phase. This technique can be used to avoid the effect of the errors related to the phase acquisition and to further develop new efficient and robust techniques capable of phase retrieval from amplitude-only acquisitions allowing for cost and complexity reduction of the measurement setup. A short review of the state-of-theart in antenna metrology is presented in this chapter, as well as a description of conventional indirect off-axis techniques applied to this field. Last sections are devoted to the description of novel measurement techniques developed by the authors in order to overcome the main limitations of the conventional methods.

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Section: Introductionmentioning

confidence: 99%

Indirect Off-Axis Holography for Antenna Metrology

Arboleya

Laviada

Ala‐Laurinaho³

et al. 2017

Holographic Materials and Optical Systems

View full text Add to dashboard Cite

show abstract

“…This suggestion has enabled the development of the innovative spiral scanning techniques [18][19][20][21][22][23][24][25][26][27][28][29]. Besides the use of continuous movements, the drastic time saving characterizing these scanning techniques is due to the significantly reduced number of needed NF data related to the application of the aforementioned nonredundant sampling representations, which can be further lowered if the surface Σ enclosing the AUT fits better its actual shape.…”

Section: Introductionmentioning

confidence: 99%

Far-Field Reconstruction From Near-Field Data Acquired via a Fast Spherical Spiral Scan: Experimental Evidences

D’Agostino¹,

Ferrara²,

Gennarelli

et al. 2013

PIER

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Abstract-A probe-compensated near-field-far-field (NF-FF) transformation with spherical spiral scanning, which makes possible to lower the number of needed measurements, as well as the time required for the data acquisition when characterizing quasi-planar antennas, is experimentally verified in this paper. Such a technique, based on the nonredundant representation of electromagnetic fields, has been achieved by properly applying the unified theory of spiral scans for nonspherical antennas and adopting a very flexible source modelling, formed by two circular "bowls" with the same aperture diameter but different bending radii. A two-dimensional optimal sampling interpolation formula allows one to reconstruct the NF data at any point on the measurement sphere and, in particular, at those required by the classical NF-FF transformation with spherical scanning. The reported NF and FF reconstructions, obtained from the nonredundant samples acquired on the spiral, assess the accuracy of the proposed technique.

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“…An effective planar spiral scanning technique described in [14] utilizes ellipsoidal modelling of the source [13] instead of the spherical one. The said technique gives the freedom of considering measurement plane at distances smaller than one half of the antenna size, and therefore increases the valid angle associated with the size of the scan plane for quasi-planar antennas.…”

Section: Introductionmentioning

confidence: 99%

Adaptive Sampling in Multilevel Plane Wave Based Near-Field Far-Field Transformed Planar Near-Field Measurements

Qureshi¹,

Schmidt²,

Eibert³

2012

PIER

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Abstract-An adaptive approach to minimize acquisition time in planar near-field antenna measurements is described. In contrast to the traditional planar near-field scanning, the presented technique acquires the near-field in form of rectangular rings and skips sampling points in smoothly varying near-field regions. Abrupt changes in the nearfield are detected by comparing extrapolated and measured near-field values at coarser sampling points. A decision function based on the signal-to-noise ratio (SNR) of the measured value is used to determine the threshold difference between the measured and the extrapolated near-field values for skipping the sampling point. Near-field data thus collected on the resultant irregular grid is processed using the multilevel plane wave based near-field far-field transformation algorithm. The multilevel transformation algorithm is computationally efficient and capable of handling data collected on irregular grids. A rigorous analysis of the adaptive data acquisition approach is then performed in terms of transformed far-field accuracy, decision factor, and test time reduction. Several test cases covering a variety of antennas are shown using synthetic as well as measured data for realistic results. Afterwards the acquisition time for the worst case scenario is compared with the traditional planar near-field measurement technique.

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An Effective NF-FF Transformation Technique With Planar Spiral Scanning Tailored For Quasi-Planar Antennas

Cited by 40 publications

References 12 publications

Indirect Off-Axis Holography for Antenna Metrology

Indirect Off-Axis Holography for Antenna Metrology

Far-Field Reconstruction From Near-Field Data Acquired via a Fast Spherical Spiral Scan: Experimental Evidences

Adaptive Sampling in Multilevel Plane Wave Based Near-Field Far-Field Transformed Planar Near-Field Measurements

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