NDF of the Near-Zone Field on a Line Perpendicular to the Source

Pierri, Rocco; Moretta, Raffaele

doi:10.1109/access.2021.3092171

Cited by 7 publications

(3 citation statements)

References 41 publications

(38 reference statements)

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“…Classical sampling schemes of the radiated field for the case of planar [12], cylindrical [13] and spherical scanning [14] were proposed. Despite this, such schemes do not take into account explicitly the source shape; for such reason, they require collecting a number of field measurements that may be significantly higher than the number of degrees of freedom (NDF) of the radiated field [15,16]. The latter represents the number of independent parameters required to represent the radiated field with good accuracy and, at the same time, the minimum number of field measurements required to reconstruct the source current stably.…”

Section: Literature Reviewmentioning

confidence: 99%

Optimal Field Sampling of Arc Sources via Asymptotic Study of the Radiation Operator

et al. 2022

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In this paper, the question of how to efficiently sample the field radiated by a circumference arc source is addressed. Classical sampling strategies require the acquisition of a redundant number of field measurements that can make the acquisition time prohibitive. For such reason, the paper aims at finding the minimum number of basis functions representing the radiated field with good accuracy and at providing an interpolation formula of the radiated field that exploits a non-redundant number of field samples. To achieve the first task, the number of relevant singular values of the radiation operator is computed by exploiting a weighted adjoint operator. In particular, the kernel of the related eigenvalue problem is first evaluated asymptotically; then, a warping transformation and a proper choice of the weight function are employed to recast such a kernel as a convolution and bandlimited function of sinc type. Finally, the number of significant singular values of the radiation operator is found by invoking the Slepian–Pollak results. The second task is achieved by exploiting a Shannon sampling expansion of the reduced field. The analysis is developed for both the far and the near fields radiated by a 2D scalar arc source observed on a circumference arc.

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Section: Literature Reviewmentioning

confidence: 99%

Optimal Field Sampling of Arc Sources via Asymptotic Study of the Radiation Operator

et al. 2022

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“…A closed-form expression of the operator T z T † zw is provided in [40]. Hence, on the basis of such result, an approximation of the point spread function in the observation domain is given by…”

Section: The Role Of the Distance Between The Scanning Linesmentioning

confidence: 99%

The Dimension of Phaseless Near-Field Data by Asymptotic Investigation of the Lifting Operator

2021

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In this paper, the question of evaluating the dimension of data space in an inverse source problem from near-field phaseless data is addressed. The study is developed for a 2D scalar geometry made up by a magnetic current strip whose square magnitude of the radiated field is observed in near non-reactive zone on multiple lines parallel to the source. With the aim of estimating the dimension of data space, at first, the lifting technique is exploited to recast the quadratic model as a linear one. After, the singular values decomposition of such linear operator is introduced. Finally, the dimension of data space is evaluated by quantifying the number of “relevant” singular values. In the last part of the article, some numerical simulations that corroborate the analytical estimation of data space dimension are shown.

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“…By definition, such a number represents the "essential dimension" of the field space [22] [23]. It can be evaluated by determining the number of relevant singular values of the radiation operator T relating the source current J with the near field E [24] [25].…”

Section: Introductionmentioning

confidence: 99%

Planar near-field antenna measurements with a uniform step larger than half-wavelength

Moretta,

Pascariello,

Petraglia

et al. 2024

Preprint

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In this paper, a new sampling scheme of the near field radiated by a planar source is proposed and assessed. More in detail, the paper shows a uniform sampling criterion that allows representing the near field over a plane with a number of measurements lower than the classical half-wavelength sampling. At first, a discretization strategy of the near field based on the warping method is recalled from the literature. The latter requires to collect a non-redundant number of field measurements that are non-uniformly arranged over the observation domain. Despite this, the warping sampling scheme works well only if the measurement plane does not overcome the source. When the observation domain is larger, it does not predict the exact positions of the field samples at the edges of the measurement plane; accordingly, in these regions it is not possible to recover the near field behavior by the collected samples. To overcome this drawback, a spatially varying oversampling is exploited. The latter is chosen in such a way that the resulting sampling becomes uniform. Such choice also ensures a growth of the sampling rate only at the edges of the observation domain permitting the retrieval of the near field by its samples. Finally, numerical simulations based on experimental data corroborate the effectiveness of the approach in recovering both the near and the far field.

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NDF of the Near-Zone Field on a Line Perpendicular to the Source

Cited by 7 publications

References 41 publications

Optimal Field Sampling of Arc Sources via Asymptotic Study of the Radiation Operator

Optimal Field Sampling of Arc Sources via Asymptotic Study of the Radiation Operator

The Dimension of Phaseless Near-Field Data by Asymptotic Investigation of the Lifting Operator

Planar near-field antenna measurements with a uniform step larger than half-wavelength

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