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  • 1.
    Kovačević-Badstüebner, Ivana
    et al.
    Advanced Power Semiconductor Laboratory, ETH Zurich, 8092 Zurich, Switzerland.
    Romano, Daniele
    UAq EMC Laboratory, Department of Industrial and Information Engineering and Economics, University of L’Aquila, 67100 L’Aquila, Italy.
    Lombardi, Luigi
    Micron Semiconductor Italia S.r.l., 67051 Avezzano, Italy.
    Grossner, Ulrike
    Advanced Power Semiconductor Laboratory, ETH Zurich, 8092 Zurich, Switzerland.
    Ekman, Jonas
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Antonini, Giulio
    UAq EMC Laboratory, Department of Industrial and Information Engineering and Economics, University of L’Aquila, 67100 L’Aquila, Italy.
    Accurate Calculation of Partial Inductances for the Orthogonal PEEC Formulation2020Ingår i: IEEE transactions on electromagnetic compatibility (Print), ISSN 0018-9375, E-ISSN 1558-187XArtikel i tidskrift (Refereegranskat)
    Abstract [en]

    The Partial Element Equivalent Circuit (PEEC) method is promising numerical technique for three-dimension electromagnetic modeling across various application fields. In the framework of the PEEC method, the partial elements modeling the magnetic and electric field coupling between elementary volumes and surfaces are computed by double-folded volume and surface integrals. Assuming the quasi-static hypothesis and an orthogonal mesh, the integrals have been computed by the analytical formulas derived in literature, which significantly reduces the computational time in comparison to the numerical integration. However, the existing analytical formulas are affected by significant numerical errors for certain PEEC structural mesh necessary to model the skin and proximity effects with a higher accuracy. To utilize the full potential of the PEEC method, the calculation of partial elements has to be carefully addressed, which has not been investigated in a comprehensive way so far. Accordingly, this paper presents a systematic accuracy analysis of the existing closed-form analytical formulas and methods for calculating the self and mutual inductances between two rectangular conductors. Additionally, a new strategy to select a proper analytical formula depending on the dimensions and positions of two conductors is proposed, which allows the mutual inductance extraction with a relative error of less than 0.1 % . The new method is systematically validated on examples of 3-D dense PEEC systems using the quadruple precision arithmetic as reference.

  • 2.
    Hartman, Andreas
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Antonini, Giulio
    UAq EMC Laboratory, Dipartimento di Ingegneria Industriale e dell’Informazione e di Economia, Universita’ degli Studi dell’Aquila, L’Aquila, Italy.
    Ekman, Jonas
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    De Lauretis, Maria
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Bandlimited Distortionless Material Design by an Approximation of the Heaviside Condition2020Ingår i: IEEE transactions on electromagnetic compatibility (Print), ISSN 0018-9375, E-ISSN 1558-187X, Vol. 62, nr 2, s. 532-541Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The distortionless propagation of signals in a medium offers a way to preserve the signal integrity. There exists a condition for distortionless propagation on a transmission line known as the Heaviside condition. This paper proposes the use of the Heaviside condition to characterize and design magnetodielectric materials that provide distortionless propagation in a specified finite frequency band. Plane wave propagation in a magneto-dielectric material is modeled by a transmission line model, thereby assuming TEM mode propagation. Then, the Heaviside condition is employed to derive the frequency-dependent permittivity and permeability functions of the material in rational form, so they satisfy the condition in a specified frequency interval. A procedure to design such materials is described. A numerical example of the design process is provided and an illustration of the effectiveness of modeled material in fulfilling the Heaviside condition in a specified frequency interval both in the time and frequency domains is given, indicating the validity of the approximation. The design procedure areas such a suitable preliminary design guide for deriving a realizable description of a magneto-dielectric, exhibiting the distortionless property in the desired frequency interval, with certain specified requirements put on the loss, or the permeability and permittivity values satisfied. The obtained results may initiate further investigations into the bandwidth restrictions of the approximation, on closed-form design solutions, and the practical realization of such materials.

  • 3.
    Antonini, Giulio
    et al.
    University of L'Aquila (Italy).
    De Lauretis, Maria
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Ekman, Jonas
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Miroshnikova, Elena
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Matematiska vetenskaper.
    On the passivity of the Delay-Rational Green’s-function-based model for Transmission Lines2019Ingår i: Analysis, Probability, Applications, and Computation: Proceedings of the 11th ISAAC Congress / [ed] Karl‐Olof Lindahl,Torsten Lindström, Luigi G. Rodino, Joachim Toft, Patrik Wahlberg, 2019, s. 71-81Konferensbidrag (Refereegranskat)
    Abstract [en]

    In this paper, we study the delay-rational Green’s-function-based (DeRaG) model for transmission lines. This model is described in terms of impedance representation and it contains a rational and a hyperbolic part. The crucial property of transmission lines models is to be passive. The passivity of the rational part has been studied by the authors in a previous work. Here, we extend the results to the rational part of the DeRaG model. Moreover, we prove the passivity of the hyperbolic part. 

  • 4.
    Romano, Daniele
    et al.
    UAq EMC Laboratory, Department of Industrial and Information Engineering and Economics, University of L’Aquila, L’Aquila, Italy .
    Kovačević-Badstübner, Ivana
    Advanced Power Semiconductor Laboratory, ETH Zurich, Zurich, Switzerland.
    Parise, Mauro
    Unit of Electrical Engineering, University Campus Bio-Medico of Rome, Rome, Italy.
    Grossner, Ulrike
    Advanced Power Semiconductor Laboratory, ETH Zurich, Zurich, Switzerland.
    Ekman, Jonas
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Antonini, Giulio
    UAq EMC Laboratory, Department of Industrial and Information Engineering and Economics, University of L’Aquila, L’Aquila, Italy.
    Rigorous dc Solution of Partial Element Equivalent Circuit Models Including Conductive, Dielectric, and Magnetic Materials2019Ingår i: IEEE transactions on electromagnetic compatibility (Print), ISSN 0018-9375, E-ISSN 1558-187XArtikel i tidskrift (Refereegranskat)
    Abstract [en]

    This paper presents a rigorous derivation of the dc solution of three-dimensional partial element equivalent circuit (PEEC) formulation extended to include simultaneously conductive, dielectric, and magnetic materials. The circuit interpretation of Maxwell’s equations provided by the PEEC method allows to reformulate the dc modeling task in such a way that physical phenomena are fully exploited. Indeed, since the displacements currents are identically zero in dielectrics, Kirchhoff’s current law is enforced in terms of charge conservation internally to dielectrics or at the interface between dielectrics and other materials. A well-posed problem is achieved by adding the charges as new unknowns and identifying the disconnected objects. Two numerical examples are presented demonstrating the accuracy of the proposed method when compared to the dc solution as extracted by the fast Fourier transform of the impulse response and a finite element method simulation.

  • 5.
    Biello, Elia
    et al.
    Dipartimento di Ingegneria Industriale e dell'Informazione e di Economi, Università degli Studi dell'Aquila.
    Antonini, Giulio
    Dipartimento di Ingegneria Industriale e dell'Informazione e di Economi, Università degli Studi dell'Aquila.
    De Lauretis, Maria
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Ekman, Jonas
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    A delay‐rational model of electromagnetic interference on multiconductor transmission lines2018Ingår i: International journal of numerical modelling, ISSN 0894-3370, E-ISSN 1099-1204, Vol. 31, nr 4, artikel-id 2342Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Multiconductor transmission lines have found a wide range of applications, as power lines, as high‐speed interconnects, and as on‐chip interconnects. Electromagnetic interference (EMI) can be described in terms of plane waves that couple to these lines, leading to unwanted disturbance. This paper presents a delayed spectral formulation for the analysis of plane‐wave coupling to multiconductor transmission lines in both the frequency and time domains, called the DeRaG‐EMI model (short for “delay‐rational model based on Green's functions for electromagnetic interference”). The model is based on Green's functions and is described in terms of delayed differential equations in the time domain. The model is suitable for studying the EMI on multiconductor transmission lines in the case of incident fields. The coupling of a plane wave to a line is described in terms of equivalent sources that account for both the delay of the line and the delays of the incoming plane wave. The delay is explicitly extracted and incorporated into the model with hyperbolic functions. The DeRaG‐EMI model does not require any segmentation of the line. Numerical results confirm its accuracy and its improved performance compared with the previous spectral model and with the inverse fast Fourier transform technique.

  • 6.
    Kovačević-Badstübner, Ivana
    et al.
    Advanced Power Semiconductor Laboratory, ETH Zurich, Zurich.
    Grossner, Ulrike
    Advanced Power Semiconductor Laboratory, ETH Zurich, Zurich.
    Romano, Daniele
    University of L'Aquila, L'Aquila, Italy.
    Antonini, Giulio
    University of L'Aquila, L'Aquila, Italy.
    Ekman, Jonas
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    A more accurate electromagnetic modeling of WBG power modules2018Ingår i: Proceedings of the International Symposium on Power Semiconductor Devices and ICs, Institute of Electrical and Electronics Engineers (IEEE), 2018, s. 260-263Konferensbidrag (Refereegranskat)
    Abstract [en]

    A major requirement for further development of wide-band gap (WBG) power devices and their applications is the optimization of packages and PCB layouts to enable fast-switching capabilities. Electromagnetic modelling allows the prediction of parasitic inductances, capacitances, and resistances of the current paths within power modules, which cannot be easily approached in measurements. As a result, electromagnetic-circuit-coupled modeling enables the optimization of package layouts and interconnections before manufacturing actual power modules. The accuracy and limitations of present numerical techniques for three-dimensional (3D) electromagnetic modeling of power modules is still neither well understood nor verified. This paper presents the extraction of parasitics of power semiconductor packages using two electromagnetic modelling approaches. The first approach is based on a well-established 3D electromagnetic quasi-static solver, ANSYS Q3D Extractor. For the second approach, a numerical solver based on the Partial Element Equivalent Circuit (PEEC) method is developed and assessed in terms of modelling accuracy required by fast switching WBG-based power converters. The PEEC method is presented as a promising numerical technique, which can potentially be used to overcome the limitations of the EM modeling based on the ANSYS Q3D Extractor.

  • 7.
    De Lauretis, Maria
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Antonini, Giulio
    University of L'Aquila .
    Ekman, Jonas
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    A Simulink implementation of the Delay-Rational Green's-Function-based Method for Multiconductor Transmission Lines2018Ingår i: EMC Europe 2018, Piscataway, NJ: Institute of Electrical and Electronics Engineers (IEEE), 2018, s. 817-822, artikel-id 8485071Konferensbidrag (Refereegranskat)
    Abstract [en]

    The electromagnetic compatibility (EMC) performances of a product can seriously be affected by interconnects. Interconnects can be studied by using the multiconductor transmission lines (MTLs) theory. Mathematical models of MTLs are normally validated with the aid of well-known software, such as MATLAB or PSpice. Simulink is part of the MATLAB suite but is not frequently used, and it is often underestimated both in academia and in the university education. In this paper, we briefly review the mathematical model for MTLs called DeRaG, which is a rational model based on delay extraction. Then, we propose the corresponding Simulink implementation for a 3-conductor transmission line. The Simulink has high readability, is accurate and the simulation time is remarkably faster than the corresponding model obtained in PSpice.

  • 8.
    Kovačević-Badstübner, Ivana
    et al.
    Advanced Power Semiconductor Laboratory, ETH Zurich, Switzerland.
    Romano, Daniele
    University of L’Aquila, L’Aquila, Italy.
    Antonini, Giulio
    University of L’Aquila, L’Aquila, Italy.
    Ekman, Jonas
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Grossner, Ulrike
    Advanced Power Semiconductor Laboratory, ETH Zurich, Switzerland.
    Electromagnetic Modeling Approaches Towards Virtual Prototyping of WBG Power Electronics2018Ingår i: 2018 International Power Electronics Conference (IPEC-Niigata 2018 -ECCE Asia), Piscataway, NJ: IEEE, 2018, s. 3588-3595, artikel-id 8507365Konferensbidrag (Refereegranskat)
    Abstract [en]

    High frequency power electronics utilizing wide-band gap semiconductor devices imposes more stringent requirements for highly accurate extraction of parasitics of power electronics systems in a wide frequency range. This paper presents the state-of-the-art modeling approaches used to predict the electromagnetic behavior of power electronic systems and components in terms of accuracy and computational cost. The potential of the Partial Element Equivalent Circuit (PEEC) technique for virtual prototyping of power electronic systems is assessed. The main advantage of this numerical technique is its capability for direct coupling between the circuit and electromagnetic domains provided by the PEEC meshing of three-dimensional geometries in partial elements. The aim of this paper is to provide a more comprehensive understanding of PEEC-based modeling for power electronics packaging.

  • 9.
    Lombardi, Luigi
    et al.
    UAq EMC Laboratory, Dipartimento di Ingegneria Industriale e dell'Informazione e di Economia, Università degli Studi dell'Aquila, Italy.
    Antonini, Giulio
    UAq EMC Laboratory, Dipartimento di Ingegneria Industriale e dell'Informazione e di Economia, Università degli Studi dell'Aquila, Italy.
    De Lauretis, Maria
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Jonas, Ekman
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    On the Distortionless Propagation in Multiconductor Transmission Lines2018Ingår i: IEEE Transactions on Components, Packaging, and Manufacturing Technology, ISSN 2156-3950, E-ISSN 2156-3985, Vol. 8, nr 4, s. 538-545Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In this paper, we investigate the distortionless conditions for multiconductor transmission lines (MTLs) with frequency-independent per-unit-length (p.u.l.) parameters. In fact, the well-known distortionless Heaviside condition is valid only for single-conductor transmission lines. The MTL is modeled using the delayed Green's-function-based method recently proposed by the authors. In this method, the impedance matrix is described in terms of a rational part, which accounts for the low-frequency behavior, and a hyperbolic part, which determines the high-frequency response of the MTL. We find that the hyperbolic part is already distortionless at high frequency and that this property can be used to identify the p.u.l. parameters of the distortionless lossy MTL associated with the original line. To serve this purpose, the line is decoupled using a frequency-independent modal decomposition. The Heaviside condition can be enforced in the modal domain on each of the single-conductor decoupled lines. The features of the distortionless lines in the modal domain are preserved in the physical domain as a consequence of the real-valued similarity transform. The numerical results demonstrate that the new line completely characterizes the distortionless propagation of a generic MTL with frequency-independent p.u.l. parameters. The proposed formulation could be used in the optimization design process by enforcing the distortionless condition along with other design constraints.

  • 10.
    Hartman, Andreas
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Romano, Daniele
    UAq EMC Laboratory, Dipartimento di Ingegneria Industriale e dell’Informazione e di Economia, Università degli Studi dell’Aquila.
    Antonini, Giulio
    UAq EMC Laboratory, Dipartimento di Ingegneria Industriale e dell’Informazione e di Economia, Università degli Studi dell’Aquila.
    Ekman, Jonas
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Partial Element Equivalent Circuit Models of Three-Dimensional Geometries Including Anisotropic Dielectrics2018Ingår i: IEEE transactions on electromagnetic compatibility (Print), ISSN 0018-9375, E-ISSN 1558-187X, Vol. 60, nr 3, s. 696-704Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    During recent years anisotropic materials have received an increasing interest and found important applications in the field of shielding and antennas. The anisotropy may be due to intrinsic properties, or as a consequence of mixing. Intentionally or not, the anisotropy impacts the electromagnetic (EM) behavior of a system. Therefore, it is desirable to be able to incorporate the anisotropic effects in an EM model, to allow design tasks and analysis. In this paper, the partial element equivalent circuit (PEEC) formulation is extended to handle nondispersive linear anisotropic dielectrics. The anisotropic dielectric PEEC cell is derived and the resulting PEEC equations are developed into a descriptor system form, which is well suited for implementation in SPICE-like solvers, and for reduction by model-order reduction techniques. A verification of the model is given by a numerical example of a patch antenna situated on an anisotropic substrate and the results are in good agreement with a finite-difference time-domain implementation. The proposed PEEC model is of interest for further work, i.e., in the modeling of setups involving mixtures of materials, with an orientational alignment, and engineered materials, encountered in different EM compatibility applications.

  • 11.
    Hartman, Andreas
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Ekman, Jonas
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Lang, Defeng
    SKF Research & Technology Development, Nieuwegein, The Netherlands.
    Romano, Daniele
    E dell'Informazione e di Economia, Università degli Studi dell’ Aquila, Dipartimento di Ingegneria Industriale, L’ Aquila, Italy.
    Antonini, Giulio
    E dell'Informazione e di Economia, Università degli Studi dell’ Aquila, Dipartimento di Ingegneria Industriale, L’ Aquila, Italy.
    PEEC Models of Printed Antennas in Condition Monitoring Applications Covered by Dielectrics with Temperature-Dependent Permittivity2018Ingår i: 2018 International Symposium on Electromagnetic Compatibility (EMC EUROPE), Piscataway, NJ: IEEE, 2018, s. 343-348, artikel-id 8485032Konferensbidrag (Refereegranskat)
    Abstract [en]

    In wireless condition monitoring systems the antenna serves as a critical part of the data transmission link. A condition monitoring application usually pose a challenging environment for an antenna system, as they are often found in harsh machine environments. As conventional antennas usually are designed for free-space operation and for some design temperature range, the presence of additional materials and their temperature variation are commonly not accounted for. In this paper an attempt to highlight the impact of materials' temperature-dependence, in their electrical properties, on printed antenna characteristics is presented. Partial element equivalent circuit models of a common printed antenna design are developed. By incorporating temperature-dependent permittivity models of pure water, and a mixture of an industrial lubricant and water, the impact on the antenna's resonant behavior is demonstrated. The numerical examples highlight that the temperature variation in the permittivity of materials surrounding the printed antenna may impact the antenna characteristics enough to be considered in the design, if a degradation in performance is not an option.

  • 12.
    Hartman, Andreas
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Ekman, Jonas
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Antonini, Giulio
    Department of Electrical Engineering, University of L’Aquila.
    Romano, Daniele
    Dipartimento di Ingegneria Industriale e dell'Informazione e di Economia, Università degli Studi dell'Aquila.
    A Descriptor Form Implementation of PEEC Models Incorporating Dispersive and Lossy Dielectrics2016Ingår i: 2016 IEEE International Symposium on Electromagnetic Compatibility (EMC): Otawa, Canada, 25-29 July 2016, Piscataway, NJ: IEEE Computer Society, 2016, s. 206-211, artikel-id 7571645Konferensbidrag (Refereegranskat)
    Abstract [en]

    With rising frequencies involved in electronics, losses and dispersion exhibited by dielectrics become important to consider in electromagnetic modeling. The Partial Element Equivalent Circuit (PEEC) method is suitable for a mixed electromagnetic and circuit setting, forming equivalent circuits that can be interconnected with circuit elements. In this paper, a descriptor form representation of PEEC models incorporatingdispersive and lossy dielectrics is developed. By representing the electrical permittivity with a Debye-Lorentz model equivalent circuits can be synthesized. The synthesized circuits for the permittivity are included in the PEEC equations by formulating the circuit equations for the additional circuit unknowns. This yields an input/output formulation that can handle an arbitrary number of finite dielectrics and be integrated by any kind of integration scheme. Furthermore, it offers a straightforward way to incorporate lossy and dispersive dielectrics into a PEEC solver compared to using recursive convolution. The proposed descriptor form representation is tested for a setup consisting of three microstrips over a ground plane, separated by a dielectric substrate. Both the ideal and the lossy and dispersive case are tested and compared. Furthermore, the proposed formulation is verified against an existing implementation in the frequency domain. Good agreement between the proposed formulation andthe existing frequency-domain PEEC formulation is obtained.

  • 13.
    De Lauretis, Maria
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Ekman, Jonas
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Antonini, Giulio
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB. Università Degli Studi di l'Aquila.
    A SPICE Realization of the Delay-Rational Green's-Function-based Method for Multiconductor Transmission Lines2016Ingår i: IEEE transactions on electromagnetic compatibility (Print), ISSN 0018-9375, E-ISSN 1558-187X, Vol. 58, nr 4, s. 1158-1168Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Virtual prototyping has become an unavoidable step in the design of electrical and electronic systems.In this context, time-domain models have to be efficiently embedded in circuit simulator environments, such as SPICE-like transient simulators.Recently, the authors focused on the interconnections, modeled using the multiconductor transmission lines theory, and a Delay-Rational method has been developed, based on Green's functions and line-delay extraction.This work presents a SPICE synthesis of the Delay-Rational method previously developed by the authors.The solution was tested for three transmission lines with frequency-independent per-unit-length parameters.We compared the SPICE results of the Delay-Rational method with those of two standard techniques: one based on a pure rational model and one based on the inverse fast Fourier transform.The time-domain simulations in SPICE of the Delay-Rational method show both accuracy and a remarkable reduction in the number of components used with respect to a purely rational approach, by virtue of the delay extraction.

  • 14.
    Mäkitaavola, Karola
    et al.
    LKAB, Luossavaara Kiirunavaara Aktiebolag.
    Stöckel, Britt-Mari
    LKAB, Luossavaara Kiirunavaara Aktiebolag.
    Sjöberg, Jonny
    Itasca Consultants AB.
    Hobbs, Stephen
    Cranfield University.
    Ekman, Jonas
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Henschel, Michael
    MDA Geospatial Serv, Ottawa.
    Wickramanayake, Aurora
    Application of InSAR for monitoring deformations at the Kiirunavaara Mine2016Ingår i: Operational and Environmental Mine Health and Safety Practice and Innovation / [ed] Mitri, H; Shnorhokian, S; Kumral, M; Sasmito, A; Sainoki, A, Montreal: McGill University. , 2016, s. 133-139Konferensbidrag (Refereegranskat)
    Abstract [en]

    An integral part of sublevel cave underground mining is the associated caving of the surrounding host rock. This causes mining-induced ground surface deformations on both the hangingwall and footwall side of the orebody. The municipality of Kiruna, in northern Sweden, is located in close proximity to the LKAB Kiirunavaara mine and is thus unavoidably affected by the mining activities. To be able to plan for an urban transformation, as the effects of mining approach the city infrastructure, it is necessary to monitor the ground deformations on a regular basis. Historically, GPS-monitoring has been used, with an extensive network of measurement hubs in place. New techniques for monitoring ground deformations are, however, constantly evaluated. As part of this process, LKAB has conducted a five-year research and development project on deformation measurements using radar satellites and the InSAR technology. The project has included a monitoring component and a research-and technology transfer component. The overall findings of the monitoring program, and the associated research and development work are presented. Particular emphasis is put on achieved accuracy and the implications for the ability to reliably monitor the progressing deformations toward the municipality and existing infrastructure. Lessons learnt from the conducted work are presented, followed by recommendations on future use of InSAR for this type of application

  • 15.
    De Lauretis, Maria
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Ekman, Jonas
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Antonini, Giulio
    University of L'Aquila .
    Delayed-rational Green's-function-based method of transmission lines and the Heaviside condition2016Ingår i: 2016 IEEE Electrical Design of Advanced Packaging and Systems Symposium, EDAPS 2016, Piscataway, NJ: Institute of Electrical and Electronics Engineers (IEEE), 2016, s. 143--145, artikel-id 7893147Konferensbidrag (Refereegranskat)
    Abstract [en]

    In electronics as well as in communications, it ishighly desirable to be able to transmit a signal that is preservedfrom any distortions that is due to the lossy nature of themedium in which the signal travels, normally a transmission line.In this paper, we exploit the connections between the delayedGreen’s-function-based method from the authors and the wellknowndistortionless Heaviside condition. It is found that, inthe method, an important results was already present but itsimportance not yet understood. In particular, we prove that weare able to identify the distortionless transmission line associatedto a generic transmission line. We consider only 1-conductortransmission lines, with frequency-independent per-unit-lengthparameters. The multiconductor transmission-line case will beaddressed in future works.

    Ladda ner (pdf)
    DeRaG_heaviside
  • 16.
    Wickramanayake, Anura
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Hanshel, Michael
    MDA.
    Hobbs, Stephen
    Cranfield University.
    Buehler, Stefan
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Rymdteknik.
    Ekman, Jonas
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Lehrbass, Brad
    MDA Geospatial Services.
    Seasonal Variation of Coherence in SAR Interferograms in Kiruna, Northern Sweden2016Ingår i: International Journal of Remote Sensing, ISSN 0143-1161, E-ISSN 1366-5901, Vol. 37, nr 2, s. 370-387Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This article presents the results of a study conducted to quantify the seasonal variation of coherence in synthetic aperture radar (SAR) interferograms in Kiruna, Northern Sweden. In SAR interferometry (InSAR), coherence is an important concept that provides a good indication of the phase stability of the scatterers. Therefore, in this study, the degree of coherence is used as a parameter to identify the seasonal variation interferograms. For this study, 34 Radarsat-2 ultra-fine beam mode (U6D) images of the Kiruna area (67°51ʹN, 20°14ʹE) and the improved digital elevation model (DEM) created by merging the Radarsat-2 DEM and ASTER DEM were used to produce 561 differential interferograms. The interferograms were arranged in three different ways for the analysis, with the first including common master interferograms (with the summer master image), the second including the sequential interferograms that have the shortest temporal baseline, and the third accounting for all possible combinations of the interferograms (full network of interferograms). Following this step, the variation of coherence for forest areas, urban areas, and flat waste rock areas was studied. This study shows that interferograms generated for the Kiruna region exhibit seasonal variations in coherence due to the ground snow layer in winter. Furthermore, when there is water on the ground due to the melting of the snow layer (in the spring) or due to rains in autumn, the coherence is reduced considerably. Another significant feature is that there is a significant change in summer-to-summer coherence for some regions even over the course of a few years. Based on this study, it is clear that the winter Radarsat-2 U6D beam mode images are not suitable for differential interferometric SAR (DInSAR) deformation measurements in flat waste rock regions in Kiruna. It is expected that even with winter images, PSInSAR or CTM techniques will be able to provide better deformation measurements, but, in this study, those techniques were not assessed. The next step will be to study the seasonal variations in coherence in natural or man-made targets/persistent scatterers using persistent scatter InSAR (PSInSAR) or coherence target monitoring (CTM) techniques

  • 17.
    De Lauretis, Maria
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Antonini, Giulio
    Department of Electrical Engineering, University of L’Aquila.
    Ekman, Jonas
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    A Delay-Rational Model of Lossy Multiconductor Transmission Lines with Frequency Independent Per-Unit-Length Parameters2015Ingår i: IEEE transactions on electromagnetic compatibility (Print), ISSN 0018-9375, E-ISSN 1558-187X, Vol. 57, nr 5, s. 1235-1245Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Cables, printed circuit boards, and VLSI interconnects are commonly modelled as multiconductor transmission lines. Models of electrically long transmission lines are memory and time consuming. In this paper, a robust and efficient algorithmfor the generation of a delay-based model is presented. The impedance representation via the open-end matrix Z is analyzed. In particular, the rational formulation of Z in terms of poles and residues is exploited for both lossless and lossy cases. The delaysof the lines are identified, and explicitly incorporated into the model. A model order reduction of the system is automatically performed, since only a limited number of poles and residues are included in the rational part of the model, whereas the highfrequency behaviour is captured by means of closed expressions that accounts for the delays. The proposed method is applied to two relevant examples and validated through the comparison with reference methods. The time domain solver is found to be more accurate and significantly faster than the one obtained froma pure-rational model.

  • 18.
    De Lauretis, Maria
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Ekman, Jonas
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Antonini, Giulio
    Department of Electrical Engineering, University of L’Aquila.
    Delay-Rational Model of Lossy and Dispersive Multiconductor Transmission Lines2015Ingår i: IEEE International Symposium on Electromagnetic Compatibility (EMC), 2015 [joint conference with] EMC Europe: Dresden, 16-22 Aug. 2015, Piscataway,NJ: IEEE Communications Society, 2015, s. 969-974, artikel-id 7256297Konferensbidrag (Refereegranskat)
    Abstract [en]

    In this paper, the transient analysis of lossy anddispersive multiconductor transmission lines is considered. Theexisting Green’s function-based method is extended to explicitlyinclude delays extraction, thus leading to a significant compressedtime-domain state-space model. The proposed method is mainlybased on poles and residues asymptotic analysis and losslessdelays extraction. The resulting hybrid state-space model incorporatesDirac-combs in the input and results into a reducednumber of state variables. A test case has been considered inorder to clearly demonstrate the effectiveness of the proposedmethodology. The results are compared with the original rationalGreen’s function method, and with the standard inverse fastFourier transform technique.

  • 19.
    De Lauretis, Maria
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Ekman, Jonas
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Antonini, Giulio
    Department of Electrical Engineering, University of L’Aquila.
    Romano, Daniele
    University of L’Aquila.
    Enhanced Delay-Rational Green's Method for Cable Time Domain Analysis2015Ingår i: 2015 International Conference on Electromagnetics in Advanced Applications (ICEAA): Turin, 7-11 Sept. 2015, Piscataway, NJ: IEEE Communications Society, 2015, s. 1228-1231Konferensbidrag (Refereegranskat)
    Abstract [en]

    State-space models of multiconductor transmissionlines can be generated by means of the Green’s function basedmethod which allows to write the open-end impedance in arational form as an infinite sum of “modal impedances”. Itcan be then embedded in a circuit simulation environment forefficient time domain analysis. The previous rational approachhas been improved through a proper mathematical formulation,that makes use of explicit delay extraction and pole/residueasymptotic behavior. Nevertheless, the computation of the polesbecomes computationally expensive when the number of conductorsincreases, since the zeros of high order polynomials haveto be evaluated. A rational fitting over the “modal impedances”is proposed, which allows a fast identification of the poles that,together with the delays, model the high frequency behavior ofthe cable in terms of standard hyperbolic functions. The lowfrequencybehavior is captured by a reduced size state-spacemodel, via rational fitting. Numerical results confirm the accuracyof the proposed modeling approach for electrically long cables,with a large number of conductors.

  • 20.
    Ekman, Jonas
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Antti, Marta-Lena
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Materialvetenskap.
    Martin-Torres, Javier
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Rymdteknik.
    Emami, Reza
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Rymdteknik.
    Törlind, Peter
    Luleå tekniska universitet, Institutionen för ekonomi, teknik och samhälle, Innovation och Design.
    Kuhn, Thomas
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Rymdteknik.
    Nilsson, Hans
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Maskinelement.
    Minami, Ichiro
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Maskinelement.
    Öhrwall Rönnbäck, Anna
    Gustafsson, Magnus
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Materialvetenskap.
    Zorzano Mier, María-Paz
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Rymdteknik.
    Milz, Mathias
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Rymdteknik.
    Grahn, Mattias
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Parida, Vinit
    Luleå tekniska universitet, Institutionen för ekonomi, teknik och samhälle, Innovation och Design.
    Behar, Etienne
    Luleå tekniska universitet, Institutionen för system- och rymdteknik.
    Wolf, Veronika
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Rymdteknik.
    Dordlofva, Christo
    Luleå tekniska universitet, Institutionen för ekonomi, teknik och samhälle, Innovation och Design.
    Mendaza de Cal, Maria Teresa
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Rymdteknik.
    Jamali, Maryam
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Rymdteknik.
    Roos, Tobias
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Rymdteknik.
    Ottemark, Rikard
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Rymdteknik.
    Nieto, Chris
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Rymdteknik.
    Soria Salinas, Álvaro Tomás
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Rymdteknik.
    Vázquez Martín, Sandra
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Rymdteknik.
    Nyberg, Erik
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Maskinelement.
    Neikter, Magnus
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Materialvetenskap.
    Lindwall, Angelica
    Luleå tekniska universitet, Institutionen för ekonomi, teknik och samhälle, Innovation och Design.
    Fakhardji, Wissam
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Materialvetenskap.
    Projekt: Rymdforskarskolan2015Övrigt (Övrig (populärvetenskap, debatt, mm))
    Abstract [en]

    The Graduate School of Space Technology

  • 21.
    Romano, Daniele
    et al.
    University of L’Aquila.
    Antonini, Giulio
    University of L’Aquila.
    Daroui, Danesh
    Ekman, Jonas
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    A Fast Sparse Reluctance- and Capacitance-Based Solver for the Partial Element Equivalent Circuit Method2014Ingår i: IEEE transactions on electromagnetic compatibility (Print), ISSN 0018-9375, E-ISSN 1558-187X, Vol. 56, nr 5, s. 1077-1085Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A new technique for the reluctance method applied to the Partial Element Equivalent Circuit (PEEC) method for the time domain analysis is presented which is well suited tobe combined with acceleration techniques. In particular, taking advantage of the rank-deficiency of the magnetic and electric field couplings, a new technique for the sparsification of reluctance and capacitance matrices is adopted. Furthermore, the multiscale block decomposition technique has been applied to fast fill these matrices. Finally, the the sparse multifrontal LU factorization has been adopted to efficiently compute the global solution. Numerical results demonstrate the validity of the proposed approach.

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  • 22.
    Safavi, Sohrab
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Ekman, Jonas
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    A hybrid PEEC--SPICE method for time-domain simulation of mixed nonlinear circuits and electromagnetic problems2014Ingår i: IEEE transactions on electromagnetic compatibility (Print), ISSN 0018-9375, E-ISSN 1558-187X, Vol. 56, nr 4, s. 912-922Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The simulation of mixed circuit and electromagnetic (EM) structures is of major interest in most EM applications. Many of the developed methods involve modifying a SPICE-like solver to incorporate an EM numerical method, or to extend the EM numerical method to handle the circuit components (e.g., diodes, transistors, etc.) by reimplementing their model definitions. A novel technique has been developed to simulate combined linear/nonlinear circuit and EM problems in time domain. This technique utilizes the partial element equivalent circuit method as the EM solver and employs OrCAD as the circuit solver. The link between the two solvers is established by defining the circuits connected to the EM structure as ports and approximating each port's current--voltage relations at each time point by a system of linear equations. To demonstrate the capability of the developed method, four structures are examined. Good agreement of the results shows the feasibility of the developed method to solve this type of mixed problems. Since OrCAD is used for the circuit simulations, the need to modify a SPICE-like solver or to reimplement the definitions of the circuit devices has been removed. On the other hand, by manipulating the system of equations and proper optimization techniques, an optimal solver can be achieved.

  • 23.
    Safavi, Sohrab
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Ekman, Jonas
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Block Factorization of the Time Domain PEEC Systems Connected to Linear and Nonlinear Circuits2014Konferensbidrag (Refereegranskat)
    Abstract [en]

    Utilizing the Partial Element Equivalent Circuit (PEEC) method to simulate electromagnetic structures attached to linear and nonlinear circuits has been proved to be a promising approach for this type of problems. The PEEC method offers an equivalent circuit for any electromagnetic structure which in turn can be connected to any linear or nonlinear circuit. A blocked structure exists in the resulted system matrix. This pattern offers an opportunity to devise customized factorization methods to solve the system of equations in a faster and optimal way. In this paper, a novel factorization technique has been proposed which reduces the computational cost to a great extent. Instead of calculating the LU factorization of the whole system at eachiteration, the LU factorization has been obtained by updating the LU factorization at the previous iteration with much fewer numerical operations. A great speed up in the simulation has been achieved.

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  • 24.
    De Lauretis, Maria
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB. Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Ekman, Jonas
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Antonini, Giulio
    Università Degli Studi dell'Aquila.
    Delayed Impedance Models of Two-Conductor Transmission Lines2014Ingår i: 2014 International Symposium on Electromagnetic Compatibility - EMC Europe 2014: Swedish Exhibition and Congress Centre, Gothenburg, Sweden : 1 - 4 September, Piscataway, NJ: IEEE Communications Society, 2014, s. 670-675, artikel-id 6930989Konferensbidrag (Refereegranskat)
    Abstract [en]

    This paper presents a new delayed model of two-conductortransmission lines with frequency-independent per-unit-length parameters. In particular, the line delay extractionproblem is considered. By use of a dyadic Green’s functionmacromodel method, the rational form of the open-endimpedance matrix allows an easy identification of poles andresidues, and a new technique for the extraction of the linedelay in an analytical way is gained, without any impact onthe complexity of the line macromodel itself. By use of Laplaceand Fourier transforms, the transfer function is expressed interms of the Dirac comb. The delay is then easily identified anddirectly incorporated into the system impulse response. Giving acurrent-controlled representation, the port voltages are evaluated.Thanks to the formulation of the transfer function by use ofthe Dirac comb, the convolution product is avoided, gainingaccuracy and time-saving from a computational point of view.Numerical results confirm the validity of the proposed delay-extractiontechnique. The basic ideas for the extension of theproposed technique to the lossy case are outlined.

  • 25.
    Daroui, Danesh
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Ekman, Jonas
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    PEEC-based Simulations Using Iterative Method and Regularization Technique for Power Electronic Applications2014Ingår i: IEEE transactions on electromagnetic compatibility (Print), ISSN 0018-9375, E-ISSN 1558-187X, Vol. 56, nr 6, s. 1448-1456Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The partial element equivalent circuit (PEEC) method has been widely used in different industrial and scientific fields for electromagnetic analysis. PEEC-based solvers have been optimized and accelerated in order to be able to solve larger and more complex problems that arise in industry. In power electronic system simulations, PEEC models are often simplified by neglecting electric field couplings and using quasi-static model. The simplified system can be further accelerated using reluctance technique and then sparsified up to high levels without degrading the accuracy of the solution. In previous work, the sparse system was solved using sparse direct solution, while in this study, an iterative approach is employed which resulted in lower time complexity of the solution. However, since matrices achieved from PEEC equations are severely ill-conditioned, regularization techniques need to be applied to avoid numerical instabilities. The regularization is done mathematically and can be interpreted as adding a frequency-dependent pseudocapacitor to each node in the PEEC model. Because the pseudocapacitors are frequency dependent, hence frequencies close to dc are not covered in this study and have left as future work. The new sparse and regularized system can then be solved using a Schur complement technique together with iterative solvers with a novel preconditioning approach.

  • 26.
    Ekman, Jonas
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Borg, Johan
    Johansson, Jonny
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Lindgren, Per
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    De Lauretis, Maria
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Lindner, Marcus
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Nilsson, Joakim
    Projekt: Frekvensomriktares funktion i beredskapskritiska system2014Övrigt (Övrig (populärvetenskap, debatt, mm))
    Abstract [sv]

    Vid dödnätstart av produktionsanläggningar och drift av svaga nät eller ö-drift är frekvensomriktare som driver pumpar och fläktar kritiska komponenter. Om frekvensomriktare påverkas av störningar i nätet kan elproduktion kopplas bort och det svaga nätet eller ö-driften kollapsa. Projektet ska studera frekvensomriktare ur ett antal aspekter såsom uppbyggnad, styrning och implementering i syfte att utveckla mer robusta frekvensomriktare och implementering av dessa för att säkerställa drift av svaga nät och ö-drift och minimera ytterligare driftstörningar vid svåra påfrestningar på elnätet.

  • 27.
    Ekman, Jonas
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Antonini, Giulio
    Department of Electrical Engineering, University of L’Aquila.
    Tutorial on Partial Element Equivalent Circuit (PEEC) method based analysis of EMC problems2014Konferensbidrag (Övrigt vetenskapligt)
    Abstract [en]

    As a tool for prediction of electromagnetic field phenomena in electric and electronics design, the Partial Element Equivalent Circuit (PEEC) method has received a great interest over the last years. Besides being a powerful full-wave 3-d numerical method which competes with other popular techniques (FDTD, FEM,MoM) it is especially suited for mixed electromagnetic circuit problems, in both the time and frequency domains. The recent literature is confirming that the PEEC method is becoming more and more popular in EMC-EMI-Signal Integrity areas especially for its capability to combine electromagnetic fields and lumped elements in the same numerical framework [1]–[3]. Furthermore its recent extension to magnetic materials and the development of fast solvers have made it powerful and well tailored for a comprehensive treatment of EMC problems.The aim of the tutorial is to present the basic theory of the method up to the most recent advancements of the technique. Furthermore, in order to make it easier for the audience, a step-by-step implementation of the method clarifying the key points to make it fast and efficient will be presented. The tutorial will be subdivided into three sections, dealing with:1) History of PEEC. Inductance calculations from Rosa through Grover to Ruehli;2) Most recent progress of the method (acceleration techniques, dispersive dielectrics, and magnetic materials);3) Circuit and electromagnetic co-simulation for active, non-linear circuit systems.

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  • 28.
    Ekman, Jonas
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Johansson, Jonny
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Lindgren, Per
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Borg, Johan
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Variable-Frequency Drives: Three perspectives2014Konferensbidrag (Refereegranskat)
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  • 29.
    Safavi, Sohrab
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Ekman, Jonas
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    A hybrid method for simulation of mixed circuit and electromagnetic problems in frequency domain2013Konferensbidrag (Refereegranskat)
    Abstract [en]

    The simulation of mixed circuit and electromagnetic (EM) structures in frequency domain has application in most electromagnetic problems. Many of the developed methods work by modifying a SPICE-like solver to incorporate an EM numerical method, or to extend the EM numerical method to handle the circuit components (e.g. diodes, transistors, ..) by re-implementing their model definitions. In order to find the frequency response of the system, a DC bias point calculation is required for which a novel hybrid technique has been proposed. This technique utilizes the Partial Element Equivalent Circuit (PEEC) method as the EM solver and employs OrCAD as the circuit solver. The link between the two solvers is acquired by defining the circuits connected to the EM structure as ports. Each port’s current-voltage relations are approximated by a linear system of equations and the Newton-Raphson algorithm is employed to calculate the bias point of the whole structure. Having the bias points, the frequency behavior of the system is acquired by calculating the admittance models of the ports using OrCAD. To demonstrate the capability of the developed method, a high frequency amplifier circuit connected to two transmission lines is examined. The results show good agreement and acceptable accuracy has been obtained that shows the feasibility of the developed method to solve this type of mixed problems. Since OrCAD is held responsible for the circuit simulations, the need to modify a SPICE-like solver or to re-implement the definitions of the circuit devices has been removed. On the other hand, by manipulating the system of equations and proper optimization techniques, an optimal solver can be achieved.

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  • 30.
    Ekman, Jonas
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Aktivitet: Medlem i betygskommitté2012Övrigt (Övrig (populärvetenskap, debatt, mm))
    Abstract [sv]

    Kelin Jia, KTH.

  • 31.
    Ekman, Jonas
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Aktivitet: Opponent vid licentiatseminarium2012Övrigt (Övrig (populärvetenskap, debatt, mm))
    Abstract [en]

    "Analysis and implementation of Switch Mode Power Supplies in MHz frequency region", Abdul Majid at Mid Sweden University.

  • 32.
    Ekman, Jonas
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Aktivitet: Opponent vid licentiatseminarium2012Övrigt (Övrig (populärvetenskap, debatt, mm))
    Abstract [en]

    Abdul Majid, Mid Sweden University

  • 33.
    Daroui, Danesh
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Ekman, Jonas
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Efficient PEEC-based simulations using reluctance method for power electronic applications2012Ingår i: Applied Computational Electromagnetics Society Journal, ISSN 1054-4887, Vol. 27, nr 10, s. 830-841Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This paper presents a partial element equivalent circuit (PEEC)-based solver that has been accelerated to exploit the massively parallel structure of graphics processing unit (GPU) technology, in order to employ a reluctance-based method in an efficient way. A grouping algorithm is also presented which makes reluctance calculation efficient, suitable for GPUs, and feasible even for very large problems. It has been shown that by using the reluctance method, the coefficient matrix in the system equation can be safely sparsified whilst the required accuracy is maintained. Because the calculation of the reluctance matrix includes matrix inversion, which is a task with high computational complexity, GPUs as cooperative units are utilized to reduce computational costs by taking advantage of parallelism. Two test models have been simulated and analyzed to benchmark the solver, and the results have been compared with the previously developed solver. Furthermore, analyzing the results reveals that the reluctance method makes it possible to use a considerably sparser system and thereby solve large problems by decreasing the memory demands and the solution time. It is also proven that the solution is reliable and accurate, whereas the problem has become noticeably smaller.

  • 34.
    Cottet, Didier
    et al.
    ABB Corporate Research.
    Stevanovic, Ivica
    ABB Corporate Research.
    Wunsch, Bernhard
    ABB Corporate Research.
    Daroui, Danesh
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Ekman, Jonas
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Antonini, Giulio
    University of L’Aquila.
    EM simulation of planar bus bars in multi-level power converters2012Ingår i: EMC Europe 2012: International Symposium on Electromagnetic Compatibillity, September 15-21, Rome, Italy, 2012Konferensbidrag (Refereegranskat)
    Abstract [en]

    This paper presents recent progress in the acceleration of PEEC based electromagnetic simulations and its impact on the design of complex bus bar structures as used in multi-level power converters. The approach presented consists of providing different dedicated acceleration methods for the different design tasks. The first acceleration technique applied is the so called reluctance matrix method for full 3D field results, reducing memory consumption by orders of magnitude and computing time by a factor 3 to 5. The second acceleration method applied is based on model order reduction techniques for port-to-port impedance extraction, reducing the computation time by several orders of magnitude and allowing wideband macro modeling for system level simulations. The paper focuses on the application of these methods showing the impact on practical bus bar design tasks

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  • 35.
    Safavi, Sohrab
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Ekman, Jonas
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Feasibility analysis of specialized PEEC solvers in comparison to SPICE-like solvers2012Ingår i: Journal of Computational Electronics, ISSN 1569-8025, E-ISSN 1572-8137, Vol. 11, nr 4, s. 440-452Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The Partial Element Equivalent Circuit ({PEEC}) method provides an electric equivalent circuit for a physical geometry. This circuit can be combined with external passive/active lumped elements, enabling the simulation of combined circuit and electromagnetic (EM) structures. The resulted circuit can be solved in dedicated solver, or equivalently can be exported to a SPICE-like solver. In this paper, the inclusion of passive and active lumped circuit elements in {PEEC} method has been studied and a combined solver has been developed. To demonstrate the capability of the solver, three structures are examined. All examples include a transmission line-PEEC model and active components. Results are compared with those from OrCAD, where an analytical model for the transmission line is used. Good agreement between the results shows the feasibility of using {PEEC} to solve this type of mixed problems. Also, comparison has been made in terms of implementation and feasibility for the aim of developing the optimal EM solver with active elements support. It is shown that SPICE is not a suitable choice to solve the PEEC models and, a specialized solver can solve the system in a much faster way. On the other hand, all the definitions and models of circuit devices e.g. transistors, MOSFETs, etc. should be implemented in the specialized solver, which raises a trade-off between the solution time and the implementation time.

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  • 36.
    Daroui, Danesh
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Ekman, Jonas
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Iterative PEEC-based power electronic systems simulations using reluctance and regularization techniques2012Ingår i: EMC Europe 2012: International Symposium on Electromagnetic Compatibillity, September 15-21, Rome, Italy, 2012Konferensbidrag (Refereegranskat)
    Abstract [en]

    This paper presents a method to deal with the ill-posed and rank-deficient linear systems arising from sparsified partial element equivalent circuit-based electromagnetic simulations via a reluctance method. Since conventional, direct methods, cannot be used to solve these kind of problems, regularization techniques need to be employed. Among various regularization techniques, a least square-based method entitled LSQR is utilized to solve the rank-deficient problems. The proposed method is specially proper for the models where capacitive couplings can be neglected, since magnetic field is the dominating factor, like problems within power electronics. The correctness of the presented PEEC-based solver is ensured by studying bus bar models which are a part of frequency converters with application in power electronics.

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  • 37.
    Wickramanayake, Anura
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Ekman, Jonas
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Buehler, Stefan
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Rymdteknik.
    Hobbs, Stephen
    School of Engineering, Cranfield University, Cranfield, Bedford.
    Mine induced deformation measurements using SAR interferometry at high latitudes2012Konferensbidrag (Refereegranskat)
  • 38.
    Daroui, Danesh
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Ekman, Jonas
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Performance analysis of parallel non-orthogonal PEEC-based solver for EMC applications2012Ingår i: Progress in Electromagnetics Research B, ISSN 1937-6472, E-ISSN 1937-6472, Vol. 41, s. 77-100Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A parallel implementation of a quasi-static Partial Element Equivalent Circuit (PEEC)-based solver that can handle electromagnetic problems with non-orthogonal structures is presented in this paper. The solver has been written in C++ and employs GMM++ and ScaLAPACK computational libraries to make the solver fast, efficient, and adaptable to current parallel computer systems. The parallel PEEC-based solver has been tested and studied on high performance computing clusters and the correctness of the solver has been verified by doing comparisons between results from orthogonal routines and also another type of electromagnetic solver, namely FEKO. Two non-orthogonal numerical test cases have been analysed in the time and frequency domain. The results are given for solution time and memory consumption while bottlenecks are pointed out and discussed. The benchmarks show a good speedup which gets improved as the problem size is increased. With the capability of the presented solver, the non-orthogonal PEEC formulation is a viable tool for modelling geometrically complex problems.

  • 39.
    Safavi, Sohrab
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Ghayour, Rahim
    Shiraz University.
    Ekman, Jonas
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Physical specifications of photonic crystal slab lenses and their effects on image quality2012Ingår i: Journal of the Optical Society of America. B, Optical physics, ISSN 0740-3224, E-ISSN 1520-8540, Vol. 29, nr 7, s. 1829-1834Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Photonic crystal (PhC) lenses with negative refractive index have attractedintense interest because of their application in optical frequencies. In thispaper, 2-D PhC lenses with triangular lattice of cylindrical holes in dielectricmaterial are investigated. Variant physical parameters of the lens are introducedand their effects on the lens response are studied in detail. The effect ofthe surface termination is investigated by analyzing the power flux within thePhC structure. A new lens formula has been obtained which shows a linearrelation between source distance (distance between the source and the lens)and image distance (distance between the image and the lens) for any surfacetermination of the PhC lens. It is observed that the excitation of surfacewaves does not necessarily pull the image closer to the lens. The effects of thethickness and the lateral width of the lens are also analyzed.

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  • 40.
    Ekman, Jonas
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Projekt: Utveckling av stabilitetskrav för fullständig integralekvationsbaserad elektromagnetisk lösare2012Övrigt (Övrig (populärvetenskap, debatt, mm))
    Abstract [sv]

    PostDoc projekt utfört vid Univ. of L'Aquila finansierat av Vetenskapsrådet.

  • 41.
    Ekman, Jonas
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Aktivitet: Arbetsmiljökommittén2011Övrigt (Övrig (populärvetenskap, debatt, mm))
    Abstract [en]

    Ledamot i LTUs arbetsmiljökommitté

  • 42.
    Ekman, Jonas
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Aktivitet: Fakultetsopponent2011Övrigt (Övrig (populärvetenskap, debatt, mm))
    Abstract [sv]

    Vid Hanif Tavakolis disputation 15 dec. 2011 vid KTH.

  • 43.
    Daroui, Danesh
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Ekman, Jonas
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Combined circuit and electromagnetic modelling on multi-core platforms2011Konferensbidrag (Refereegranskat)
    Abstract [en]

    Computer simulation techniques are widely used in various fields to design and verify the functionality, performance, quality, or safety of a product. In electrical systems, with increasing operational frequencies, capacitive and inductive couplings between parts in an embedded system might have to be taken into account. Therefore, traditional circuit analysis are not sufficient for such problems. Hence, other simulation approaches such as Partial Element Equivalent Circuit (PEEC), Method of Moments, and Finite Element Methods, and other have been developed to fulfill this need. By using the PEEC method, the simulation of the functionality of an electrical device can be combined with an electromagnetic analysis. Thus, the method has been widely used in combined circuit and electromagnetic modeling on problems in different classes in power electronic industry and antenna design. The main aim of this paper is to demonstrate how multi-core systems can contribute to improve the performance of a PEEC-based electromagnetic simulation tool and to show that the improvements make it possible to solve larger and more complex problems in a reasonable time.A PEEC-based solver has been developed at Luleå University of Technology. The kernel of the solver has been implemented in C++ and is designed to run on different desktop platforms and operating systems. It is known that in the PEEC formulations there are large, dense, and in many cases non-symmetric matrices which increase the computational costs. Hence, using an efficient and robust library as well as support for the recently advanced hardware, is vital and will highly affect the performance of the solver.

  • 44.
    Safavi, Sohrab
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Ekman, Jonas
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    On the route to full-wave electromagnetic modeling with active circuit element inclusion2011Ingår i: 2011 8th Workshop on Electromagnetic Compatibility of Integrated Circuits, Piscataway, NJ: IEEE Communications Society, 2011, s. 257-262Konferensbidrag (Refereegranskat)
    Abstract [en]

    The possibility to combine circuit and electromagnetic modeling in one program enable new problems to be solved and more efficient simulations to be done. In this paper, the inclusion of passive and active lumped circuit elements in the Partial Element Equivalent Circuit (PEEC) method has been studied and a combined solver has been developed. The solver uses PEEC to provide an equivalent circuit for a structure, then the external passive and active lumped elements are added, and then solves the combined system providing the potential and current distributions in the structure. To demonstrate the capability of the solver, two structures are examined. Both examples include a transmission line-PEEC model and active components. Results are compared with those from OrCAD, where an analytical model for the transmission line is used. Good agreement between the results shows the feasibility of using PEEC to solve this type of mixed problems.

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  • 45.
    Ekman, Jonas
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Enohnyaket, Mathias
    Project: A New Method for Combined Electric and Electromagnetic Modeling of Power Distribution Systems -High frequency models for reactors2011Övrigt (Övrig (populärvetenskap, debatt, mm))
    Abstract [en]

    The project has the following main objectives.(i) Detail an systematic approach for the generation of equivalent circuit descriptionsfor power components in the high frequency range. Demonstration include time-and frequency- domain analysis of free space coils.(ii) Introduce, evaluate, and develop the PEEC method for combined electric andelectromagnetic (EM) modeling of power components.(iii) Transfer of knowledge from microelectronics- to power engineering- modeling and simulation.

  • 46.
    Ekman, Jonas
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Wisten, Åke
    Luleå tekniska universitet, Institutionen för system- och rymdteknik.
    Project: Electromagnetic compatibility issues in the Swedish railway system2011Övrigt (Övrig (populärvetenskap, debatt, mm))
  • 47.
    Ekman, Jonas
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Safavi, Sohrab
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Project: Full-wave electromagnetic modeling with active circuit elements2011Övrigt (Övrig (populärvetenskap, debatt, mm))
    Abstract [sv]

    Syftet med doktorandprojektet är att utveckla en programvara som kan lösa kretsekvationer för passiva och aktiva komponenter samtidigt som elektromagnetiska problem beskrivna mha ekvivalenta kretsar (Eng. PEEC) löses. Projektet bygger vidare på programvara som tagits fram på EISLAB under de senaste 10 åren och som nu används i flertalet projekt med regionala, nationella och internationella parter. I feb. 2011 har doktoranden en första implementation av en fungerande PEEC-lösare som stödjer aktiva komponenter i form av transistorer (BJTs) och dioder. Nästa steg är att utöka stödet för olika transistormodeller, förna implementationen och inkorporera den i den existerande MultiPEEC-programvaran som utvecklas i ett parallellt projekt.

  • 48.
    Ekman, Jonas
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Lindgren, Tore
    Wickramanayake, Anura
    Luleå tekniska universitet, Institutionen för system- och rymdteknik.
    Project: Improved measurements of mining induced ground deformations using GPS and SAR techniques2011Övrigt (Övrig (populärvetenskap, debatt, mm))
    Abstract [en]

    The LKAB SAR project is implemented to measure the subsidence and terrain deformation around the Kiruna iron ore mine and in the Kiruna city area. The LKAB SAR project has two components. One is the monitoring component in which MDA (main contractor) provides the SAR deformation maps to LKAB and the second is the technology transfer component in where MDA provides theoretical and practical knowledge to LKAB so that LKAB can produce deformation maps by their own. And Cranfield University and Luleå University of technology will carryout the LKAB SAR research. During the SAR project it is expected to use “DInSAR” and “CTM” techniques to measure the deformations. By using DInSAR and CTM techniques, LKAB can achieve the required accuracy levels during the summer season but it is likely that the quality and quantity of the measurements will largely differ during winter season (due to the thick snow cover). Similarly, areas which have thick forest cover will prevent radar waves reaching the ground and because of that it is likely the quality and quantity of the measurements will decrease in such areas during the mid summer period. Therefore LKAB is planning to carry out a research program to improve the SAR measurements.

  • 49.
    Ekman, Jonas
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Holm, Magnus
    Delsing, Jerker
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Project: Time domain field calculations using PEEC2011Övrigt (Övrig (populärvetenskap, debatt, mm))
    Abstract [en]

    Utveckla metodik och verktyg för att simulera och undersöka sambandet mellan mjukvarudesign och elektromagnetiska fält inom inbyggda system. Mjukvaran skall skrivas i språket Timber och elektromagnetiska fält skall simuleras i PEEC. Lämpliga verktyg för att simulera hårdvara skall undersökas och tillämpas, så att ett komplett simuleringsflöde med feedback kan åstadkommas. Utveckla en designparadigm för mjukvara så att oönskade elektromagnetiska effekter och inkompatibiliteter kan undvikas.

  • 50.
    Lindgren, Tore
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Ekman, Jonas
    Backén, Staffan
    A measurement system for the complex far-field of physically large antenna arrays under noisy conditions utilizing the equivalent electric current method2010Ingår i: IEEE Transactions on Antennas and Propagation, ISSN 0018-926X, E-ISSN 1558-2221, Vol. 58, nr 10, s. 3205-3211Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Precipitation in the form of snow or rain could severely degrade the performance of large antenna arrays, in particular if knowledge about the beam shape and pointing direction in absolute numbers is necessary. In this paper, a method of estimating the far-field of each individual antenna element using the equivalent electric current approach is presented. Both a least squares estimator and a Kalman filter was used to solve the resulting system of equation and their performance was compared. Simulation results shows that the estimated far-field for one antenna element is very accurate if there is no noise on the signal. During noisier conditions the Kalman filter gives less noisy results while the systematic errors are slightly larger compared to the least squares estimator.

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