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Publications (10 of 55) Show all publications
Ghasemifard, F., Norgren, M. & Quevedo-Teruel, O. (2018). Dispersion Analysis of 2-D Glide-Symmetric Corrugated Metasurfaces Using Mode-Matching Technique. IEEE Microwave and Wireless Components Letters, 28(1), 1-3
Open this publication in new window or tab >>Dispersion Analysis of 2-D Glide-Symmetric Corrugated Metasurfaces Using Mode-Matching Technique
2018 (English)In: IEEE Microwave and Wireless Components Letters, ISSN 1531-1309, E-ISSN 1558-1764, Vol. 28, no 1, p. 1-3Article in journal (Refereed) Published
Abstract [en]

In this letter, wave propagation in 2-D doubled corrugated metasurfaces, including glide-symmetric corrugated metasurfaces, embedded in a thin parallel plate waveguide have been analyzed using the mode matching method. The general dispersion equation for propagation at different directions is derived and dispersion surfaces have been obtained for three different cases. The results are in good agreement with reference results obtained using CST Microwave Studio. Moreover, the method is accurate and computationally much faster than CST Microwave Studio and similar commercial software.

Place, publisher, year, edition, pages
IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 2018
Keywords
Corrugated surfaces, dispersion analysis, glide-symmetric metasurface, mode matching, planar lenses
National Category
Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:kth:diva-222198 (URN)10.1109/LMWC.2017.2769881 (DOI)000422937500001 ()2-s2.0-85035751387 (Scopus ID)
Note

QC 20180205

Available from: 2018-02-05 Created: 2018-02-05 Last updated: 2018-03-13Bibliographically approved
Norgren, M. (2017). On the exact solution for the eigenmodes of the tape helix. In: 2017 32nd General Assembly and Scientific Symposium of the International Union of Radio Science, URSI GASS 2017: . Paper presented at 32nd General Assembly and Scientific Symposium of the International Union of Radio Science, URSI GASS 2017, Montreal, Canada, 19 August 2017 through 26 August 2017 (pp. 1-4). Institute of Electrical and Electronics Engineers (IEEE)
Open this publication in new window or tab >>On the exact solution for the eigenmodes of the tape helix
2017 (English)In: 2017 32nd General Assembly and Scientific Symposium of the International Union of Radio Science, URSI GASS 2017, Institute of Electrical and Electronics Engineers (IEEE), 2017, p. 1-4Conference paper, Published paper (Refereed)
Abstract [en]

The eigenmodes of the tape helix are analysed by expanding the surface current density on the tape, or the tangential electric field in the interspacing gap, into Chebyshev polynomials. Numerical results for the dispersion relation, the surface current and the gap electric field are presented, and the two approaches are cross-verified against each other. The numerical stability as well as similarities and differences with other approaches are discussed.

Place, publisher, year, edition, pages
Institute of Electrical and Electronics Engineers (IEEE), 2017
National Category
Communication Systems
Identifiers
urn:nbn:se:kth:diva-229322 (URN)10.23919/URSIGASS.2017.8105034 (DOI)2-s2.0-85046278235 (Scopus ID)9789082598704 (ISBN)
Conference
32nd General Assembly and Scientific Symposium of the International Union of Radio Science, URSI GASS 2017, Montreal, Canada, 19 August 2017 through 26 August 2017
Note

QC 20180604

Available from: 2018-06-04 Created: 2018-06-04 Last updated: 2018-06-04Bibliographically approved
Ghasemifard, F. & Norgren, M. (2017). Sensor Selection via Convex Optimization in Remote Contact-free Measurement of Currents. In: 2017 International Applied Computational Electromagnetics Society Symposium - Italy, ACES 2017: . Paper presented at 2017 International Applied Computational Electromagnetics Society Symposium - Italy, ACES 2017, Firenze, Italy, 26 March 2017 through 30 March 2017. Institute of Electrical and Electronics Engineers (IEEE), Article ID 7916351.
Open this publication in new window or tab >>Sensor Selection via Convex Optimization in Remote Contact-free Measurement of Currents
2017 (English)In: 2017 International Applied Computational Electromagnetics Society Symposium - Italy, ACES 2017, Institute of Electrical and Electronics Engineers (IEEE), 2017, article id 7916351Conference paper, Published paper (Refereed)
Abstract [en]

The sensor positions have substantial effect on the accuracy of remote contact-free reconstruction of currents in power transmission lines from magnetic field data, measured by a set of sensors located under the conductors. By maximizing a performance metric, based on the Fisher information matrix, Nopt sensors are selected from N candidate sensors. The main optimization problem is changed to a convex optimization problem using a relaxation of the integer constraints. The result for optimized sensor positions for a remote current reconstruction in power transmission lines using a planar sensor array is demonstrated.

Place, publisher, year, edition, pages
Institute of Electrical and Electronics Engineers (IEEE), 2017
National Category
Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:kth:diva-199687 (URN)10.23919/ROPACES.2017.7916351 (DOI)2-s2.0-85020042728 (Scopus ID)9780996007832 (ISBN)
Conference
2017 International Applied Computational Electromagnetics Society Symposium - Italy, ACES 2017, Firenze, Italy, 26 March 2017 through 30 March 2017
Note

QC 20170116

Available from: 2017-01-13 Created: 2017-01-13 Last updated: 2017-06-22Bibliographically approved
Ghasemifard, F. & Norgren, M. (2017). Sensor Selection via Convex Optimization in Remote Contact-free Measurement of Currents. In: 2017 INTERNATIONAL APPLIED COMPUTATIONAL ELECTROMAGNETICS SOCIETY SYMPOSIUM - ITALY (ACES): . Paper presented at International Applied-Computational-Electromagnetics-Society Symposium - Italy (ACES), MAR 26-30, 2017, Firenze, ITALY. IEEE
Open this publication in new window or tab >>Sensor Selection via Convex Optimization in Remote Contact-free Measurement of Currents
2017 (English)In: 2017 INTERNATIONAL APPLIED COMPUTATIONAL ELECTROMAGNETICS SOCIETY SYMPOSIUM - ITALY (ACES), IEEE , 2017Conference paper, Published paper (Refereed)
Abstract [en]

The sensor positions have substantial effect on the accuracy of remote contact-free reconstruction of currents in power transmission lines from magnetic field data, measured by a set of sensors located under the conductors. By maximizing a performance metric, based on the Fisher information matrix, Nopt sensors are selected from N candidate sensors. The main optimization problem is changed to a convex optimization problem using a relaxation of the integer constraints. The result for optimized sensor positions for a remote current reconstruction in power transmission lines using a planar sensor array is demonstrated.

Place, publisher, year, edition, pages
IEEE, 2017
National Category
Signal Processing
Identifiers
urn:nbn:se:kth:diva-214908 (URN)000408977800140 ()2-s2.0-85020042728 (Scopus ID)978-0-9960078-3-2 (ISBN)
Conference
International Applied-Computational-Electromagnetics-Society Symposium - Italy (ACES), MAR 26-30, 2017, Firenze, ITALY
Note

QC 20171020

Available from: 2017-10-20 Created: 2017-10-20 Last updated: 2018-03-12Bibliographically approved
Dalarsson, M. & Norgren, M. (2016). Boundary shape reconstructions in a coaxial waveguide using Bessel functions. In: 2016 URSI INTERNATIONAL SYMPOSIUM ON ELECTROMAGNETIC THEORY (EMTS): . Paper presented at URSI International Symposium on Electromagnetic Theory (EMTS), AUG 14-18, 2016, Espoo, FINLAND (pp. 826-829). IEEE
Open this publication in new window or tab >>Boundary shape reconstructions in a coaxial waveguide using Bessel functions
2016 (English)In: 2016 URSI INTERNATIONAL SYMPOSIUM ON ELECTROMAGNETIC THEORY (EMTS), IEEE, 2016, p. 826-829Conference paper, Published paper (Refereed)
Abstract [en]

This paper investigates boundary shape reconstructions in coaxial waveguides using microwave scattering. Electromagnetic field perturbation theory together with inverse problem theory is used to reconstruct two-dimensional small boundary deformations on the inner boundary of a coaxial waveguide. Due to the first-order perturbation theory employed, the scattering parameters of the waveguide have linear dependencies on the continuous deformation function. Thus, the corresponding inverse problem can be linearized, and direct inversion can be employed to obtain the shape parameters. Tikhonov regularization is used to regularize the resulting ill-conditioned linear system. Finally, reconstruction results are presented for a few examples of two-dimensional localized shape deformations of coaxial waveguide boundaries, being in agreement with the actual shapes.

Place, publisher, year, edition, pages
IEEE, 2016
Series
URSI International Symposium on Electromagnetic Theory, ISSN 2163-405X
National Category
Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:kth:diva-200039 (URN)10.1109/URSI-EMTS.2016.7571531 (DOI)000389770800237 ()2-s2.0-84992065262 (Scopus ID)978-1-5090-2502-2 (ISBN)
Conference
URSI International Symposium on Electromagnetic Theory (EMTS), AUG 14-18, 2016, Espoo, FINLAND
Note

QC 20170126

Available from: 2017-01-26 Created: 2017-01-20 Last updated: 2017-01-26Bibliographically approved
Ghasemifard, F. & Norgren, M. (2016). Contact-free Measurement of Currents inTwo-dimensional Parallel Conductors Using the Green Identity Approach. In: 2016 URSI International Symposium on Electromagnetic Theory, EMTS 2016: . Paper presented at 2016 URSI International Symposium on Electromagnetic Theory, EMTS 2016; Espoo; Finland; 14 August 2016 through 18 August 2016 (pp. 338-340). IEEE, Article ID 7571391.
Open this publication in new window or tab >>Contact-free Measurement of Currents inTwo-dimensional Parallel Conductors Using the Green Identity Approach
2016 (English)In: 2016 URSI International Symposium on Electromagnetic Theory, EMTS 2016, IEEE, 2016, p. 338-340, article id 7571391Conference paper, Published paper (Refereed)
Abstract [en]

The Green identity approach is used to reconstructcurrents in very long parallel conductors above the groundfrom magnetic field data measured at some points under theconductors. By assuming that the conductor positions are known,this method can be used for contact-free measurement of currentsin transmission lines in power system. This method gives thepossibility of measuring high-frequency currents which cannotbe measured with current transformers.

Place, publisher, year, edition, pages
IEEE, 2016
National Category
Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:kth:diva-199633 (URN)10.1109/URSI-EMTS.2016.7571391 (DOI)000389770800097 ()2-s2.0-84992126325 (Scopus ID)978-1-5090-2502-2 (ISBN)
Conference
2016 URSI International Symposium on Electromagnetic Theory, EMTS 2016; Espoo; Finland; 14 August 2016 through 18 August 2016
Note

QC 20170116

Available from: 2017-01-11 Created: 2017-01-11 Last updated: 2017-03-07Bibliographically approved
Ghasemifard, F., Johansson, M. & Norgren, M. (2016). Current reconstruction from magnetic field using spherical harmonic expansion to reduce impact of disturbance fields. Inverse Problems in Science and Engineering, 1-15
Open this publication in new window or tab >>Current reconstruction from magnetic field using spherical harmonic expansion to reduce impact of disturbance fields
2016 (English)In: Inverse Problems in Science and Engineering, ISSN 1741-5977, E-ISSN 1741-5985, p. 1-15Article in journal (Refereed) Published
Abstract [en]

A current reconstruction method, for determining currents in a set of parallel infinitely long conductors located above the ground from measured magnetic field, is developed. The method is designed to work even if three-dimensional external disturbance fields from external sources are present. The external field is written as an expansion in spherical harmonics. Therefore, the field in the different measurement points is regarded as a linear combination of the expansion coefficients and the currents to be determined. A linear equation system is formed with the currents and the expansion coefficients as the unknowns. The currents are reconstructed by solving the equation system using least squares method and Tikhonov regularization. If the characteristics of the ground below the conductors are known with sufficient precision, the ground effect can also be included into the model. Results of various simulations show that the method works well and noise in the measured magnetic field can be handled.

Place, publisher, year, edition, pages
Taylor & Francis Group, 2016
Keywords
Current reconstruction, inverse source problem, power line measurements, spherical harmonics, Tikhonov regularization, Ground effect, Inverse problems, Least squares approximations, Linear equations, Magnetic field measurement, Magnetic fields, Magnetism, Spheres, Power lines, Harmonic analysis
National Category
Other Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:kth:diva-197209 (URN)10.1080/17415977.2016.1201661 (DOI)000399465600002 ()2-s2.0-84976254217 (Scopus ID)
Note

QC 20161212

Available from: 2016-12-12 Created: 2016-11-30 Last updated: 2017-06-02Bibliographically approved
Norgren, M., Ghasemifard, F. & Dalarsson, M. (2016). Scattering of lower order modes in a parallel plate waveguide loaded with a slightly deformed layer of conducting strips. In: 2016 URSI INTERNATIONAL SYMPOSIUM ON ELECTROMAGNETIC THEORY (EMTS): . Paper presented at URSI International Symposium on Electromagnetic Theory (EMTS), AUG 14-18, 2016, Espoo, FINLAND (pp. 349-352). IEEE
Open this publication in new window or tab >>Scattering of lower order modes in a parallel plate waveguide loaded with a slightly deformed layer of conducting strips
2016 (English)In: 2016 URSI INTERNATIONAL SYMPOSIUM ON ELECTROMAGNETIC THEORY (EMTS), IEEE, 2016, p. 349-352Conference paper, Published paper (Refereed)
Abstract [en]

The lower order modes are derived for a parallel plate waveguide loaded with a sheet of parallel conducting strips. Using a first order perturbation method, we derive the scattering parameters due to a small deformation of the sheet. Results for scattering within and between the novel slow mode and the ubiquitous TEM-mode are presented. With increasing angle between the strips and the direction of propagation, the interaction between the slow mode and the deformation shifts downwards in frequency, due to the reduced phase velocity.

Place, publisher, year, edition, pages
IEEE, 2016
Series
URSI International Symposium on Electromagnetic Theory, ISSN 2163-405X
National Category
Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:kth:diva-200036 (URN)10.1109/URSI-EMTS.2016.7571394 (DOI)000389770800100 ()2-s2.0-84992066332 (Scopus ID)978-1-5090-2502-2 (ISBN)
Conference
URSI International Symposium on Electromagnetic Theory (EMTS), AUG 14-18, 2016, Espoo, FINLAND
Note

QC 20170126

Available from: 2017-01-26 Created: 2017-01-20 Last updated: 2017-01-26Bibliographically approved
Dalarsson, M., Norgren, M. & Jaksic, Z. (2015). Exact Analytical Solution for Fields in a Lossy Cylindrical Structure with Linear Gradient Index Metamaterials. Progress In Electromagnetics Research, 151, 109-117
Open this publication in new window or tab >>Exact Analytical Solution for Fields in a Lossy Cylindrical Structure with Linear Gradient Index Metamaterials
2015 (English)In: Progress In Electromagnetics Research, ISSN 1070-4698, E-ISSN 1559-8985, Vol. 151, p. 109-117Article in journal (Refereed) Published
Abstract [en]

We investigate the electromagnetic wave propagation across a finite inhomogeneous and anisotropic cylindrical metamaterial composite containing both positive and negative effective refractive index parts with linear spatial gradient. Exact analytical solutions for the electric and magnetic field distributions are obtained for a linear variation of effective refractive index across the structure. The exact analytical results for the electric and magnetic fields are compared to the numerical results obtained using the numerical simulation software HFSS. The model allows for general temporal dispersion and uniform losses within the composite.

National Category
Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:kth:diva-171180 (URN)10.2528/PIER15042002 (DOI)000357107200010 ()
Note

QC 20150720

Available from: 2015-07-20 Created: 2015-07-20 Last updated: 2017-12-04Bibliographically approved
Ghasemifard, F. & Norgren, M. (2015). Handling the ill-posedness of current retrieval in power lines from magnetic field data using Tikhonov regularization method. In: 2015 USNC-URSI Radio Science Meeting (Joint with AP-S Symposium), USNC-URSI 2015 - Proceedings: . Paper presented at USNC-URSI Radio Science Meeting (Joint with AP-S Symposium), USNC-URSI 2015; Westin Bayshore Vancouver HotelVancouver; Canada (pp. 56-56). 978-147997817-5: IEEE
Open this publication in new window or tab >>Handling the ill-posedness of current retrieval in power lines from magnetic field data using Tikhonov regularization method
2015 (English)In: 2015 USNC-URSI Radio Science Meeting (Joint with AP-S Symposium), USNC-URSI 2015 - Proceedings, 978-147997817-5: IEEE , 2015, p. 56-56Conference paper, Published paper (Refereed)
Abstract [en]

An inverse source problem of reconstructing the currents in parallel conductor structures from magnetic field data is considered. In this kind of inverse source problems which arise in contact-free measurements of currents in bus bars, power lines, and cables, the magnetic field data collected by a set of sensors in the vicinity of the conductors is used to determine the currents in conductors. The method is based on inversion of the direct map from the currents to the magnetic field data using a proper model of the problem.

Place, publisher, year, edition, pages
978-147997817-5: IEEE, 2015
National Category
Geophysics
Identifiers
urn:nbn:se:kth:diva-186721 (URN)10.1109/USNC-URSI.2015.7303340 (DOI)000380575300056 ()2-s2.0-84954228879 (Scopus ID)
Conference
USNC-URSI Radio Science Meeting (Joint with AP-S Symposium), USNC-URSI 2015; Westin Bayshore Vancouver HotelVancouver; Canada
Note

QC 20160516

Available from: 2016-05-16 Created: 2016-05-13 Last updated: 2016-11-14Bibliographically approved
Organisations
Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0001-9241-8030

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