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Hartman, Andreas
Publications (5 of 5) Show all publications
Hartman, A., Antonini, G., Ekman, J. & De Lauretis, M. (2019). Bandlimited Distortionless Material Design by an Approximation of the Heaviside Condition. IEEE transactions on electromagnetic compatibility (Print)
Open this publication in new window or tab >>Bandlimited Distortionless Material Design by an Approximation of the Heaviside Condition
2019 (English)In: IEEE transactions on electromagnetic compatibility (Print), ISSN 0018-9375, E-ISSN 1558-187XArticle in journal (Refereed) Epub ahead of print
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 magneto-dielectric 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 transverse electromagnetic 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 is as such a suitable preliminary design guide for deriving a realizable description of a magnetodielectric, 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.

Place, publisher, year, edition, pages
IEEE, 2019
Keywords
Dispersive media, distortionless propagation, Heaviside condition, magneto-dielectric media
National Category
Other Electrical Engineering, Electronic Engineering, Information Engineering
Research subject
Electronic systems
Identifiers
urn:nbn:se:ltu:diva-75287 (URN)10.1109/TEMC.2019.2910761 (DOI)
Available from: 2019-07-11 Created: 2019-07-11 Last updated: 2019-07-11
Hartman, A. (2019). Electromagnetic Modeling with Complex Dielectrics: A Partial Element Equivalent Circuit Approach. (Doctoral dissertation). Luleå: Luleå University of Technology
Open this publication in new window or tab >>Electromagnetic Modeling with Complex Dielectrics: A Partial Element Equivalent Circuit Approach
2019 (English)Doctoral thesis, comprehensive summary (Other academic)
Alternative title[sv]
Elektromagnetisk modellering med komplexa dielektriska material : en partiellelement ekvivalent krets-approach
Abstract [en]

Wireless communication systems have become an integral part of many complex systems in diverse areas of society, for the exchange of data in business and industrial settings. With the advent of Internet of Things (IoT) and wireless sensor network architectures, the tighter demands on interoperability between different devices are putting heavy requirements their ability to exchange data wirelessly among them reliably. However, many environments pose a challenging setting for a wireless communication system to operate within. Consequently, electromagnetic modeling could be used as a crucial part of the analysis and design of a wireless communication system in these environments.

In this thesis, means for the electromagnetic modeling of complex materials are considered. Specifically, the incorporation of dielectrics that exhibit loss, dispersion, and anisotropic properties into electromagnetic codes is addressed. The work has been executed within the partial element equivalent circuit (PEEC) method framework.

First, a PEEC implementation that incorporates dispersive and lossy dielectrics, represented by equivalent circuit models explicitly included in the PEEC equations, is developed. This provides a descriptor system form of the PEEC model that includes dielectrics with permittivities that can be represented as finite sums of Debye and Lorentz permittivity models and can be integrated by any time integration scheme of choice. Additionally, the description admits the application of model-order reduction techniques, reducing the model complexity of a large-scale PEEC model that consists of frequency-dispersive dielectrics.

Next, the incorporation of anisotropic dielectrics in PEEC simulations is considered. A PEEC cell for anisotropic dielectrics, with a general permittivity tensor, is derived. It turns out to be an extension of the standard dielectric PEEC cell for an isotropic dielectric by adding a voltage-dependent current source in parallel with the excess capacitance of the dielectric cell. A cross-coupling excess capacitance concept that defines the dependent current source for the anisotropic PEEC cell is defined and given for orthogonal PEEC meshes. As a result, the PEEC cell for an anisotropic dielectric is possible to extend to handle lossy and dispersive anisotropic dielectrics straightforwardly. The developed PEEC model has been applied to model a patch antenna mounted on an anisotropic substrate. The simulation results are in agreement with other simulation technique results. Consequently, the anisotropic model permits electromagnetic modeling of structures and devices that consist of a broader class of materials.

The modeling of dielectrics in different ambient temperature conditions is also considered for the PEEC analysis of its impact on antennas. Dielectrics with temperature dependent permittivity have been modeled with PEEC by standard approaches found in the literature. This has proved useful for frequency-domain simulations in PEEC. The utility has been demonstrated by investigating the impact due to temperature-dependent dielectrics on printed antennas. These types of investigations could provide valuable in-formation in the design of printed antennas in harsh environments.

Finally, the problem of designing magneto-dielectric materials that intrinsically provide distortionless propagation for TEM mode signals is investigated. The frequency dependent permittivity and permeability of a slab are related to the per-unit length (p.u.l.) parameters of a two-conductor transmission line. The p.u.l. parameters are specified to approximate the Heaviside condition in a specified and finite frequency interval, while simultaneously enforcing that the corresponding permittivity and permeability represent a passive material. Consequently, the passivity condition ensures the designed material is possible to realize in practice while the Heaviside condition secures that the material is distortionless. The design method has been employed to design a passive material that approximates the Heaviside condition in a narrow frequency interval. Verification in both time and frequency domains indicates that the designed material closely resembles a distortionless material in the specified frequency interval. These results indicate that an approximation of the Heaviside condition could be a potential aid in the design of distortionless materials for bandlimited applications. Further investigations on design method improvements, limitations on the approximation in terms of both accuracy and bandwidth, and the construction of such materials in practice could lead to new distortionless cable or material designs.

Place, publisher, year, edition, pages
Luleå: Luleå University of Technology, 2019
Series
Doctoral thesis / Luleå University of Technology 1 jan 1997 → …, ISSN 1402-1544
National Category
Other Electrical Engineering, Electronic Engineering, Information Engineering
Research subject
Industrial Electronics
Identifiers
urn:nbn:se:ltu:diva-72606 (URN)978-91-7790-302-4 (ISBN)978-91-7790-303-1 (ISBN)
Public defence
2019-03-27, A1547, Luleå, 10:15 (English)
Opponent
Supervisors
Available from: 2019-01-18 Created: 2019-01-17 Last updated: 2019-04-15Bibliographically approved
Hartman, A., Romano, D., Antonini, G. & Ekman, J. (2018). Partial Element Equivalent Circuit Models of Three-Dimensional Geometries Including Anisotropic Dielectrics. IEEE transactions on electromagnetic compatibility (Print), 60(3), 696-704
Open this publication in new window or tab >>Partial Element Equivalent Circuit Models of Three-Dimensional Geometries Including Anisotropic Dielectrics
2018 (English)In: IEEE transactions on electromagnetic compatibility (Print), ISSN 0018-9375, E-ISSN 1558-187X, Vol. 60, no 3, p. 696-704Article in journal (Refereed) Published
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.

Place, publisher, year, edition, pages
Institute of Electrical and Electronics Engineers (IEEE), 2018
National Category
Other Electrical Engineering, Electronic Engineering, Information Engineering
Research subject
Industrial Electronics
Identifiers
urn:nbn:se:ltu:diva-65639 (URN)10.1109/TEMC.2017.2724071 (DOI)000422793900018 ()2-s2.0-85028449937 (Scopus ID)
Note

Validerad;2018;Nivå 2;2018-01-25 (andbra)

Available from: 2017-09-14 Created: 2017-09-14 Last updated: 2019-01-17Bibliographically approved
Hartman, A., Ekman, J., Lang, D., Romano, D. & Antonini, G. (2018). PEEC Models of Printed Antennas in Condition Monitoring Applications Covered by Dielectrics with Temperature-Dependent Permittivity. In: 2018 International Symposium on Electromagnetic Compatibility (EMC EUROPE): . Paper presented at International Symposium on Electromagnetic Compatibility, EMC Europe 2018, Amsterdam, The Netherlands, 27-30 August 2018 (pp. 343-348). Piscataway, NJ: IEEE, Article ID 8485032.
Open this publication in new window or tab >>PEEC Models of Printed Antennas in Condition Monitoring Applications Covered by Dielectrics with Temperature-Dependent Permittivity
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2018 (English)In: 2018 International Symposium on Electromagnetic Compatibility (EMC EUROPE), Piscataway, NJ: IEEE, 2018, p. 343-348, article id 8485032Conference paper, Published paper (Refereed)
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.

Place, publisher, year, edition, pages
Piscataway, NJ: IEEE, 2018
Series
IEEE International Symposium on Electromagnetic Compatibility, ISSN 2158-110X
National Category
Other Electrical Engineering, Electronic Engineering, Information Engineering
Research subject
Industrial Electronics
Identifiers
urn:nbn:se:ltu:diva-72331 (URN)10.1109/EMCEurope.2018.8485032 (DOI)000454901100065 ()2-s2.0-85056091979 (Scopus ID)978-1-4673-9698-1 (ISBN)
Conference
International Symposium on Electromagnetic Compatibility, EMC Europe 2018, Amsterdam, The Netherlands, 27-30 August 2018
Available from: 2018-12-19 Created: 2018-12-19 Last updated: 2019-01-28Bibliographically approved
Hartman, A., Ekman, J., Antonini, G. & Romano, D. (2016). A Descriptor Form Implementation of PEEC Models Incorporating Dispersive and Lossy Dielectrics (ed.). In: (Ed.), 2016 IEEE International Symposium on Electromagnetic Compatibility (EMC): Otawa, Canada, 25-29 July 2016. Paper presented at IEEE International Symposium on Electromagnetic Compatibility : 25/07/2016 - 29/07/2016 (pp. 206-211). Piscataway, NJ: IEEE Computer Society, Article ID 7571645.
Open this publication in new window or tab >>A Descriptor Form Implementation of PEEC Models Incorporating Dispersive and Lossy Dielectrics
2016 (English)In: 2016 IEEE International Symposium on Electromagnetic Compatibility (EMC): Otawa, Canada, 25-29 July 2016, Piscataway, NJ: IEEE Computer Society, 2016, p. 206-211, article id 7571645Conference paper, Published paper (Refereed)
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.

Place, publisher, year, edition, pages
Piscataway, NJ: IEEE Computer Society, 2016
Series
IEEE International Symposium on Electromagnetic Compatibility, ISSN 2158-110X
National Category
Other Electrical Engineering, Electronic Engineering, Information Engineering
Research subject
Industrial Electronics
Identifiers
urn:nbn:se:ltu:diva-38090 (URN)10.1109/ISEMC.2016.7571645 (DOI)000387117700061 ()2-s2.0-84990982208 (Scopus ID)c5b527d2-5891-44b8-8ef3-78de432285db (Local ID)978-1-5090-1442-2 (ISBN)c5b527d2-5891-44b8-8ef3-78de432285db (Archive number)c5b527d2-5891-44b8-8ef3-78de432285db (OAI)
Conference
IEEE International Symposium on Electromagnetic Compatibility : 25/07/2016 - 29/07/2016
Note

Validerad; 2016; Nivå 1; 2016-12-01 (andbra)

Available from: 2016-10-03 Created: 2016-10-03 Last updated: 2019-01-17Bibliographically approved
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