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

Qureshi, M. Ayyaz; Schmidt, Carsten H.; Eibert, Thomas F.

doi:10.2528/pier12020804

Cited by 15 publications

(13 citation statements)

References 23 publications

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“…This is, however, only the case, if FFT based field transformations are utilized, which are not able to consider any a priori knowledge about the DUT. If the knowledge about the shape of the DUT is considered and more flexible field transformation approaches are employed, reduced sampling rates can be achieved for many configurations [29,30,[37][38][39].…”

Section: Planar Plane Wave Expansionmentioning

confidence: 99%

“…Also, many new insights into the algorithms are included. Further capabilities of FIAFTA including the efficient treatment of non-redundant measurements [29,30], echo suppression techniques by inward and outward looking measurement probes [31], volumetric imaging by hierarchical disaggregation of broadband field observations [32], efficient transformation of phaseless field measurements with first results [18,19], and the utilization of FIAFTA within non-linear inverse material problem solutions [14,15,33] are found in the given references. Extensive error investigations are presented in [34].…”

Section: Introductionmentioning

confidence: 99%

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ELECTROMAGNETIC FIELD TRANSFORMATIONS FOR MEASUREMENTS AND SIMULATIONS (Invited Paper)

Eibert¹,

Kılıç²,

Lopez³

et al. 2015

PIER

Self Cite

125

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Abstract-Electromagnetic field transformations are important for electromagnetic simulations and for measurements. Especially for field measurements, the influence of the measurement probe must be considered, and this can be achieved by working with weighted field transformations. This paper is a review paper on weighted field transformations, where new information on algorithmic properties and new results are also included. Starting from the spatial domain weighted radiation integral involving free space Green's functions, properties such as uniqueness and the meaning of the weighting function are discussed. Several spectral domain formulations of the weighted field transformation integrals are reviewed. The focus of the paper is on hierarchical multilevel representations of irregular field transformations with propagating plane waves on the Ewald sphere. The resulting Fast Irregular Antenna Field Transformation Algorithm (FIAFTA) is a versatile and efficient transformation technique for arbitrary antenna and scattering fields. The fields can be sampled at arbitrary irregular locations and with arbitrary measurement probes without compromising the accuracy and the efficiency of the algorithm. FIAFTA supports different equivalent sources representations of the radiation or scattering object: 1) equivalent surface current densities discretized on triangular meshes, 2) plane wave representations, 3) spherical harmonics representations. The current densities provide for excellent spatial localization and deliver most diagnostics information about the test object. A priori information about the test object can easily be incorporated, too. Using plane wave and spherical harmonics representations, the spatial localization is not as good as with spatial current densities, but still much better than in the case of conventional modal expansions. Both far-field based expansions lead to faster transformations than the equivalent currents and in particular the orthogonal spherical harmonics expansion is a very attractive and robust choice. All three expansions are well-suited for efficient echo suppression by spatial filtering. Various new field transformation and new computational performance results are shown in order to illustrate some capabilities of the algorithm.

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Section: Planar Plane Wave Expansionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

ELECTROMAGNETIC FIELD TRANSFORMATIONS FOR MEASUREMENTS AND SIMULATIONS (Invited Paper)

Eibert¹,

Kılıç²,

Lopez³

et al. 2015

PIER

Self Cite

125

View full text Add to dashboard Cite

show abstract

“…The overall effect of scan area truncation can be assumed negligible if the truncation level at the edges of the scan plane is ≤ −40 dB. Since FIAFTA can handle measurements on arbitrary grids, the valid angle of the radiation pattern can be significantly increased by utilizing adaptive sampling in planar and cylindrical measurements [33,34].…”

Section: Scan Area Truncationmentioning

confidence: 99%

Near-Field Error Analysis for Arbitrary Scanning Grids Using Fast Irregular Antenna Field Transformation Algorithm

Qureshi¹,

Schmidt²,

Eibert³

2013

PIER B

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Abstract-An extensive error analysis for arbitrary near-field antenna measurements is performed. Expressions are derived to estimate the far-field uncertainty using the available near-field data together with the measurement inaccuracy but, most importantly, without the knowledge of the reference far field. Error analysis techniques presented so far either assume a specific set of antennas or a specific measurement surface and are difficult to generalize. We present a generalized approach providing realistic error estimates using the recently developed Fast Irregular Antenna Field Transformation Algorithm (FIAFTA). FIAFTA utilizes equivalent plane wave sources to represent radiated antenna fields and is able to process nearfield data collected on arbitrary measurement grids. The unknown plane wave coefficients are determined by solving a linear system of equations. The error model is applied to planar, cylindrical, and spherical near-field measurements and is also valid for arbitrary measurement grids. The estimated far-field uncertainties show good agreement with the reference far-field errors.

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“…However, performing far-field measurements is very costly and time-consuming. Another common method of measuring PCB radiated emissions is to use a magnetic or electric field probe for near-field scanning of the PCB surface [9][10][11][12][13]. Although the associated test setup and procedure are simpler than those for far-field measurement, the near-field scan results are more effective for locating the source of radiated emission than for predicting radiated emission levels as required by EMC specifications.…”

Section: Introductionmentioning

confidence: 99%

Estimating the Reduction of Radiated Emissions From TFT-LCD Panel Using Network Analyzer With a Bulk Current Injection Probe

Ho¹,

Chen²,

Horng³

et al. 2013

PIER

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Abstract-A network analyzer with a bulk current injection (BCI) probe is proposed to measure the common-mode conversion coefficient for DC supply loops on a driver PCB of thin film transistor-liquid crystal display (TFT-LCD) panel. The proposed technique is used to predict the common-mode radiated emission caused by the DC supply loops, which highly correlates with the radiated emission measurements obtained for the TFT-LCD panel in a fully anechoic chamber (FAC). The proposed technique is also successful to estimate the reduction of a specific peak in the radiated emission spectrum by shielding the DC supply loops on a driver PCB of TFT-LCD panel. Electromagnetic simulation and equivalent-circuit modeling approaches are developed to confirm the common-mode radiation mechanism in this study.

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

Cited by 15 publications

References 23 publications

ELECTROMAGNETIC FIELD TRANSFORMATIONS FOR MEASUREMENTS AND SIMULATIONS (Invited Paper)

ELECTROMAGNETIC FIELD TRANSFORMATIONS FOR MEASUREMENTS AND SIMULATIONS (Invited Paper)

Near-Field Error Analysis for Arbitrary Scanning Grids Using Fast Irregular Antenna Field Transformation Algorithm

Estimating the Reduction of Radiated Emissions From TFT-LCD Panel Using Network Analyzer With a Bulk Current Injection Probe

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