Application of the Tikhonov Regularization Technique to the Equivalent Magnetic Currents Near-Field Technique

Colinas, Jerome; Goussard, Yves; Laurin, Jean‐Jacques

doi:10.1109/tap.2004.835232

Cited by 27 publications

(27 citation statements)

References 22 publications

(30 reference statements)

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“…Similar studies can be found in Ref. 10 in which only the equivalent magnetic current is determined from the Tikhonov SRM in the presence of a white Gaussian noise. In this example, we consider a more general problem, in which both the electric and magnetic currents are determined from the regularized and nonregularized solvers in the presence of a white Gaussian noise (Equation 1).…”

Section: Radiative Noisy Near-fieldsupporting

confidence: 79%

“…It is already known that the SRM integral equation is inherently an ill-posed problem, which means that the solution of discretized equation is very sensitive to small measurement errors and noise. To minimize the effect of errors and noise, the SRM Equation 3 should be replaced by the Tikhonov SRM equation as follows 10 :…”

Section: Overview Of Source Current Reconstruction Methodsmentioning

confidence: 99%

“…Measuring the nearfields of the antenna under test (AUT) and reconstructing the far-field (FF) radiation is one of the most widely used advanced measurement techniques. [1][2][3][4][5][6][7][8][9][10][11][12][13][14] Near-field (NF) measurements have dramatically reduced the dimensions of test facilities and test costs and increased measurement speeds.…”

Section: Introductionmentioning

confidence: 99%

“…[3][4][5][6][7][8][9][10][11] The SRM is based on reconstructing the equivalent currents at the AUT aperture from the tangential near-field measurements. The distinguishing excellence of SRM for NF/FF transformations is the validity of the SRM equation in all of the space around the AUT, while modal expansion-based NF/FF transformation can be applied outside the minimum sphere enclosing the AUT.…”

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

A decoupled source current reconstruction method for noisy and reactive near-field to far-field transformation

Bod

Sarraf-Shirazi

Moradi

et al. 2017

Int J RF Microw Comput Aided Eng

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In this article, a decoupled source current reconstruction method (SRM) for noisy and reactive near-field (NF) to far-field (FF) transformation is introduced. It is shown that the traditional SRM for NF/FF transformation shows instability in the regions that the amounts of noise or reactive radiations are noticeable. Therefore, in these regions, equivalent currents should be determined from a Tikhonov SRM equation. However, this equation increases the computational cost of the SRM. To simplify the Tikhonov SRM equation, a Tikhonov radial field retrieval algorithm is also proposed. In this algorithm, the Tikhonov integral equation is decoupled by considering and retrieving the radial components of the electric field. Results of far-field calculation with both the proposed Tikhonov SRM equation and Tikhonov radial field retrieval algorithm with three different antennas are presented and compared with those of the full-wave simulation and measurements. The results show more accurate field transformation with the proposed algorithms. K E Y W O R D Sfield transformation, reactive near-field, source current reconstruction, Tikhonov inverse problem | I NT ROD UCTI ONAdvanced and accurate measurement of the antenna radiating characteristics in a controlled environment has attracted considerable attentions in the recent years. Measuring the nearfields of the antenna under test (AUT) and reconstructing the far-field (FF) radiation is one of the most widely used advanced measurement techniques. 1-14 Near-field (NF) measurements have dramatically reduced the dimensions of test facilities and test costs and increased measurement speeds.Recently, measuring the field data in the close proximity of the radiator is also possible with the electro-optic field technology. [12][13][14][15] Although measuring the reactive near-field radiation of an AUT is a big step forward for further reducing the cost and speed of the antenna measurements, these measurement systems are applicable when a method for accurately transforming the reactive near-field to far-field radiations is also being developed. However, up to the authors' knowledge, most of the available NF to FF transformation method are placed in the region that the reactive radiations are negligible and the effects of evanescent modes on the field transformation procedure have not already studied. [1][2][3][4][5][6][7][8] For NF to FF transformation, two main methods have already been reported over the past years. The oldest method which has been used widely is the modal techniques. 1,2 Brief reports about the reactive near-field transformation with modal techniques can be found in Refs. 13 and 14. In these papers, a stable field transformation is obtained by optimizing the field sampling positions of the AUT in a way that creates a transformation matrix with the most convenient singular values. This reduces the effects of reactive radiation as will be discussed in this article.The newest method for NF to FF transformation which is more flexible but has a higher computatio...

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Section: Radiative Noisy Near-fieldsupporting

confidence: 79%

Section: Overview Of Source Current Reconstruction Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

A decoupled source current reconstruction method for noisy and reactive near-field to far-field transformation

Bod

Sarraf-Shirazi

Moradi

et al. 2017

Int J RF Microw Comput Aided Eng

View full text Add to dashboard Cite

show abstract

“…the Tikhonov regularization technique [74], [75], to obtain faithful results. These kinds of techniques, however, present some drawbacks, such as the election of the suitable parameters to obtain the best results without losing information [76], what enhances the difficulty in finding accurate results.…”

Section: Integral Equation Methodsmentioning

confidence: 99%

High-resolution algorithms for the reconstruction of the equivalent currents of an antenna by means of modal theory and a priori information

Escuderos¹

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To my parents and sister. AgradecimientosHan pasado muchos años desde que comencé esta tesis y muchas personas me han ayudado a llevarla a cabo. Algunos han estado desde el principio y otros llegaron más tarde. A todos ellos quiero dedicar esta primera parte de la tesis para darle las gracias por todo su apoyo.Mi primer agradecimiento es para mi director de tesis, Mariano Baquero. Empezamos a trabajar juntos hace más de cinco años y desde entonces siempre ha estado ahí para ayudarme con el proyecto final de carrera, con la tesina de máster y, por supuesto, con esta tesis. Aél mi más sincero agradecimiento por toda su ayuda y todo su apoyo. Espero seguir trabajando conél en el futuro, con sus enseñanzas y sus consejos.En segundo lugar quiero dar las gracias a Miguel Ferrando por su dirección del grupo durante todos estos años y su apoyo en los múltiples congresos a los que hemos asistido. También quiero agradecerle su ayuda a Alejandro Valero. Siempre que he tenido dudas ha estado ahí para resolvérmelas y ayudarme. Tampoco me puedo olvidar de Vicent Miquel Rodrigo, del que nunca me ha faltado la ayuda cuando se la he pedido.También quiero darle las gracias a todos mis compañeros y amigos durante estos años empezando, por supuesto, por Esperanza. Con ella empecé mi andadura por esta tesis y hemos pasado por todos los tramos juntos: los congresos nacionales, los internacionales, las tesinas, los cursos, etc. Me ha ayudado durante todo este tiempo y me ha animado cuando las cosas no venían bien dadas. Por eso quiero agradecerle todo su apoyo yánimo.Quiero agradecerle también de forma muy especial su ayuda a Eva, por sus consejos durante todos estos años y su decidido compromiso para que el trabajo y el grupo salieran adelante. Asimismo quiero darle las gracias a Jose Ignacio, por brindarme su ayuda cuando la he necesitado, y a Marta, por su apoyo durante todos estos años.Por supuesto, también tengo que agradecerle su ayuda y colaboración a Toni y Bernat. Sin su trabajo en el laboratorio esta tesis no hubiera sido posible. Pero además, su ayuda y apoyo fuera deél ha sido inigualable así que mi más sincero agradecimiento por todo.No puedo olvidarme tampoco de Dani, David y Felipe. Los tres están o han estado cerca durante todos estos años en los que he estado haciendo esta tesis. A los tres, gracias por vuestros consejos y ayuda, y por hacerme pasar mejor los momentos difíciles.Finalmente quiero agradecer su amistad a Marko, Michele, y Carlos. Aunque los he conocido durante poco tiempo, siempre me han prestado su ayuda cuando la he necesitado.Y, por supuesto, gracias a los que siempre estuvieron cerca: Vicente, Ariana, Miguel, Cristina, Denis, Juanma, Emilio, Jorge, Fulvio, Ana, . . . , y a mis compañeros de viaje durante todos estos años: Rubén y Dani.Enúltimo lugar, y no por ello menos importante, quiero dar las gracias a mis padres, José y Ramona, y a mi hermana, Elena. Sin ellos, estoy seguro de que esta tesis hubiera sido imposible de realizar. Gracias por la ayuda, el apoyo, la paciencia, elánimo . . . gracias p...

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Phaseless near‐field to far‐field transformation based on source current reconstruction and signal subspace optimization

Bod

Moradi

Sarraf-Shirazi

2021

Int J RF Microw Comput Aided Eng

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In this article, an algorithm for the phaseless near-field (NF) to far-field (FF) transformation based on the source current reconstruction method (SRM) is proposed. The algorithm starts with decomposing the equivalent currents of the antenna under test (AUT) into a deterministic and ambiguous current. The deterministic portion of the current is determined from the phaseless signal subspace-based optimization method (SOM), while several iterative forwardbackward propagations add the ambiguous portion. It is shown that with the SOM initialization, no further prior information about the antenna under test is needed and the iterative scheme can converge to the desired result within a few iterations. A simulation and a measurement example validate the proposed algorithm. All results show an accurate, fast, and stable phaseless field transformation is obtained.

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Application of the Tikhonov Regularization Technique to the Equivalent Magnetic Currents Near-Field Technique

Cited by 27 publications

References 22 publications

A decoupled source current reconstruction method for noisy and reactive near-field to far-field transformation

A decoupled source current reconstruction method for noisy and reactive near-field to far-field transformation

High-resolution algorithms for the reconstruction of the equivalent currents of an antenna by means of modal theory and a priori information

Phaseless near‐field to far‐field transformation based on source current reconstruction and signal subspace optimization

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