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Publications (10 of 57) Show all publications
Ghasemifard, F., Valerio, G., Norgren, M. & Quevedo-Teruel, O. (2018). Analysis of wave propagation in plasmonic holey metasurfaces with cylindrical holes. In: IET Conference Publications: . Paper presented at 12th European Conference on Antennas and Propagation, EuCAP 2018, 9 April 2018 through 13 April 2018. Institution of Engineering and Technology (CP741)
Open this publication in new window or tab >>Analysis of wave propagation in plasmonic holey metasurfaces with cylindrical holes
2018 (English)In: IET Conference Publications, Institution of Engineering and Technology , 2018, no CP741Conference paper, Published paper (Refereed)
Abstract [en]

The wave propagation along a plasmonic holey metasurface when a metallic plate is located in its proximity has been analyzed using a mode matching technique. With this analysis, we demonstrate that decreasing the distance between the metallic plate and the holey surface excites nonresonant higher order modes in the structure. Therefore, considering only the dominant mode inside the holes, as the previous simpler models assumed, is not sufficient to analyze this type of metasurfaces.

Place, publisher, year, edition, pages
Institution of Engineering and Technology, 2018
Keywords
Antenna, Dispersive analysis, Holey structure, Metasurfaces, Mode matching, Antennas, Plasmonics, Plasmons, Wave propagation, Cylindrical holes, Higher-order modes, Metallic plate, Mode matching technique, Plates (structural components)
National Category
Condensed Matter Physics
Identifiers
urn:nbn:se:kth:diva-247465 (URN)2-s2.0-85057318742 (Scopus ID)
Conference
12th European Conference on Antennas and Propagation, EuCAP 2018, 9 April 2018 through 13 April 2018
Note

QC 20190405

Available from: 2019-04-05 Created: 2019-04-05 Last updated: 2019-05-20Bibliographically approved
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: 2018-11-20Bibliographically approved
Norgren, M., de Saracho, I. O. & Dalarsson, M. (2018). Perturbation Approach to Shape Reconstruction in a Rectangular Waveguide using Experimental Data. In: 2018 INTERNATIONAL APPLIED COMPUTATIONAL ELECTROMAGNETICS SOCIETY SYMPOSIUM (ACES): . Paper presented at ACES-Denver 2018; Denver; United States; 25 March 2018 through 29 March 2018. IEEE
Open this publication in new window or tab >>Perturbation Approach to Shape Reconstruction in a Rectangular Waveguide using Experimental Data
2018 (English)In: 2018 INTERNATIONAL APPLIED COMPUTATIONAL ELECTROMAGNETICS SOCIETY SYMPOSIUM (ACES), IEEE , 2018Conference paper, Published paper (Refereed)
Abstract [en]

We consider the inverse problem of reconstructing the shape of a deformation in one of the broad walls of a rectangular waveguide. Assuming a small deformation, resulting in weak scattering, the direct problem is solved using a first order perturbation approach. Hence, the inverse problem becomes linear and is formulated as an equation system for a set of expansion coefficients. The illposedness of the inverse problem is handled with regularization, by adding a penalty term which weight is determined by the L-curve method. The theory is tested on experimental reflection data, using the dominant mode of the waveguide. The reconstructed shape is in qualitative agreement with the true shape, but a detailed resolution cannot be obtained due to insufficient quality of the experimental data. Extensions and improvements of the method are discussed.

Place, publisher, year, edition, pages
IEEE, 2018
National Category
Computational Mathematics
Identifiers
urn:nbn:se:kth:diva-231641 (URN)000435263000085 ()2-s2.0-85048342443 (Scopus ID)
Conference
ACES-Denver 2018; Denver; United States; 25 March 2018 through 29 March 2018
Note

QC 20180903

Available from: 2018-09-03 Created: 2018-09-03 Last updated: 2019-08-20Bibliographically approved
Ghasemifard, F., Norgren, M. & Quevedo-Teruel, O. (2018). Twist and Polar Glide Symmetries: an Additional Degree of Freedom to Control the Propagation Characteristics of Periodic Structures. Scientific Reports, 8
Open this publication in new window or tab >>Twist and Polar Glide Symmetries: an Additional Degree of Freedom to Control the Propagation Characteristics of Periodic Structures
2018 (English)In: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 8Article in journal, Editorial material (Refereed) Published
Abstract [en]

New high-frequency 5G and satellite communication systems require fully-metallic antennas and electromagnetic components. These components can be implemented with truncated versions of periodic structures. In order to achieve the desired performance of these future devices, it is of crucial importance to have a precise control of the propagation properties, i.e. the frequency dispersion behavior and stop-bands. Here, we demonstrate the potential use of higher symmetries to diminish the frequency dispersion of periodic structures and control the width of stop-bands with a new type of fully-metallic transmission line, which is loaded with holes on a twist-symmetric configuration. Simulated and experimental results confirm the intrinsic link between the propagation characteristics and the symmetries of a periodic structure. Additionally, we provide a definitive explanation of the recently discovered polar glide symmetry and its potential combination with twist symmetries to produce low-dispersive materials and reconfigurable stop-bands. The promising properties of these structures are demonstrated with a fully-metallic reconfigurable filter, which could be used for future high-frequency 5G and satellite communication systems.

National Category
Engineering and Technology
Identifiers
urn:nbn:se:kth:diva-239132 (URN)10.1038/s41598-018-29565-6 (DOI)000439805700027 ()2-s2.0-85050674647 (Scopus ID)
Note

QC 20181120

Available from: 2018-11-16 Created: 2018-11-16 Last updated: 2019-05-20Bibliographically 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)000408977800140 ()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: 2018-12-03Bibliographically 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
Organisations
Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0001-9241-8030

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