Efficient electromagnetic near-field computation by the multilevel fast multipole method employing mixed near-field/far-field translations

Tzoulis, A.; Eibert, Thomas F.

doi:10.1109/lawp.2005.860195

Cited by 40 publications

(21 citation statements)

References 4 publications

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“…In order to compute the electromagnetic near-and farfields from a known current distribution, the same efficient hierarchical scheme can be employed (Tzoulis and Eibert, 2005). For all lowest level MLFMM groups (smallest boxes), the computed currents are used to generate a plane wave representation of the corresponding radiated fields (Eibert, 2005).…”

Section: Methodsmentioning

confidence: 99%

Ray tracing with multi-radiation transmitters

Brem

Eibert

2012

Adv. Radio Sci.

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Abstract.A restriction in using electromagnetic ray tracing for field prediction is given by the far-field condition: the results are only valid in the far-field region of the radiator. In this paper, it will be shown how ray tracing for accurate field computation can also be applied in the near-field regions of transmitters. The reduction of required large distances between transmitter and receiver is achieved by subdividing the transmitter in smaller subtransmitters. Even for complex transmitters, e.g. antennas with objects in close proximity such as metallic carrier platforms, subtransmitter models can be very efficiently generated by using the Multilevel Fast Multipole Method (MLFMM). This well-known integral equation solving technique makes very large problems in computational electromagnetics manageable. The subtransmitters can be directly generated based on this algorithm. A simulation example will show the improved modeling accuracy and options for simplification and refinement will also be discussed.

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Section: Methodsmentioning

confidence: 99%

Ray tracing with multi-radiation transmitters

Brem

Eibert

2012

Adv. Radio Sci.

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“…r M g in (12) and (13) is therefore r M g = r M − r g . If |r M g | is considerably larger than the relevant MLFMM group dimensions and the extent of the probe antenna (i.e., some FF criterion is fulfilled) [13,14], the translation operator in (11) can be replaced by…”

Section: Model and Constraint Equationsmentioning

confidence: 99%

“…The matrix entries in (12) and (13) are written with direct translations from some MLFMM group center to probe positions. However, the evaluation can also be done in a way that the translations are performed into some MLFMM group center and the wave contributions at the probe positions are then obtained by the MLFMM typical disaggregation and anterpolation procedures [7,12,13,20].…”

Section: Model and Constraint Equationsmentioning

confidence: 99%

“…In a recent publication [7], a robust and efficient ECM has been reported by the application of the spherical harmonics expansion based MLFMM (SE-MLFMM) [12] with NF and FF translations [13,14] employed for the iterative solution of the normal equation system obtained from RWG based discretization of the ECM IE operator. In this method, an IE is formulated relating the discretized unknown equivalent surface current densities and known NF samples.…”

Section: Introductionmentioning

confidence: 99%

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Inverse Equivalent Surface Current Method With Hierarchical Higher Order Basis Functions, Full Probe Correction and Multilevel Fast Multipole Acceleration

Eibert¹,

Ismatullah²,

Kaliyaperumal³

et al. 2010

PIER

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Abstract-An inverse equivalent surface current method working with equivalent electric and/or magnetic surface current densities on appropriately chosen Huygens surfaces is investigated. The considered model with triangular surface meshes is compatible with the models known from method of moments (MoM) solutions of surface integral equations. Divergence conforming current basis functions of order 0.5 and of order 1.5 are considered, where the order 0.5 functions are the well-known Rao-Wilton-Glisson basis functions. Known near-field samples typically obtained from measurements are mapped on the unknown equivalent surface current densities utilizing the radiation integrals of the currents as forward operator, where the measurement probe influence is formulated in a MoM like weighting integral. The evaluation of the forward operator is accelerated by adaptation of the multilevel fast multipole method (MLFMM) to the inverse formulation, where the MLFMM representation is the key to full probe correction by employing only the far-field patterns of the measurement probe antennas. The resulting fully probe corrected algorithm is very flexible and efficient, where it is found that the computation speed is mostly dependent on the MLFMM configuration of the problem and not that much on the particular equivalent current expansion as long as the expansion is able to represent the currents sufficiently well. Inverse current and far-field pattern results are shown for a variety of problems, where near-field samples obtained from simulations as well as from realistic measurements are considered.

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“…Far-field translations to the measurement points fulfilling the far-field criterion for the source boxes on the given level are performed first. For every measurement point the highest level for which far-field translations may be used is determined in the pre-processing step and translations are preferably carried out on the highest possible level (Tzoulis and Eibert, 2005), since the overall number of translations is smaller for a lower number of source boxes. In the next step the plane wave spectra of the boxes on the given level are interpolated to the sampling rate on the next higher level and aggregated to the centre of the parent box.…”

Section: Hybrid Approachmentioning

confidence: 99%

Hybrid multilevel plane wave based near-field far-field transformation utilising combined near- and far-field translations

Schmidt

Eibert²

2009

Adv. Radio Sci.

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Abstract. The radiation of large antennas and those operating at low frequencies can be determined efficiently by near-field measurement techniques and a subsequent nearfield far-field transformation. Various approaches and algorithms have been researched but for electrically large antennas and irregular measurement contours advanced algorithms with low computation complexity are required. In this paper an algorithm employing plane waves as equivalent sources and utilising efficient diagonal translation operators is presented. The efficiency is further enhanced using simple farfield translations in combination with the expensive nearfield translations. In this way a low complexity near-field transformation is achieved, which works for arbitrary sample point distributions and incorporates a full probe correction without increasing the complexity.

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Efficient electromagnetic near-field computation by the multilevel fast multipole method employing mixed near-field/far-field translations

Cited by 40 publications

References 4 publications

Ray tracing with multi-radiation transmitters

Ray tracing with multi-radiation transmitters

Inverse Equivalent Surface Current Method With Hierarchical Higher Order Basis Functions, Full Probe Correction and Multilevel Fast Multipole Acceleration

Hybrid multilevel plane wave based near-field far-field transformation utilising combined near- and far-field translations

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