Sökning: "time-domain electromagnetic"

Visar resultat 21 - 25 av 52 avhandlingar innehållade orden time-domain electromagnetic.

1. 21. Efficient Adaptive Algorithms for an Electromagnetic Coefficient Inverse Problem

   Författare :John Bondestam Malmberg; Göteborgs universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; coefficient inverse problem; inverse scattering; Maxwell’s equations; approximate global convergence; finite element method; adaptivity; ; a posteriori error analysis;

   Sammanfattning : This thesis comprises five scientific papers, all of which are focusing on the inverse problem of reconstructing a dielectric permittivity which may vary in space inside a given domain. The data for the reconstruction consist of time-domain observations of the electric field, resulting from a single incident wave, on a part of the boundary of the domain under consideration. LÄS MER

3. 22. Boundary and Interface Conditions for Electromagnetic Wave Propagation using FDTD

   Författare :Jon Häggblad; Björn Engquist; Olof Runborg; Thomas Rylander; KTH; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Numerical analysis; Numerisk analys;

   Sammanfattning : Simulating electromagnetic waves is of increasing importance, for example, due to the rapidly growing demand of wireless communication in the fields of antenna design, photonics and electromagnetic compatibility (EMC). Many numerical and asymptotic techniques have been developed and one of the most common is the Finite-Difference Time-Domain (FDTD) method, also known as the Yee scheme. LÄS MER

4. 23. High Frequency Model of Electrified Railway Propulsion System for EMC Analysis

   Författare :Kelin Jia; Rajeev Thottappillil; Hans Bängtsson; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Electromagnetic compatibility; railway; propulsion system; multitransmission line; ac motor modeling; vector fitting; fast transient;

   Sammanfattning : A model of the electrified railway propulsion system working in a wide frequency range is studied in this thesis. The high frequency modeling is the first stage to study and predict the Electromagnetic compatibility (EMC) problems in the electrified railway propulsion system, which are safety and reliability issues of high concern. LÄS MER

5. 24. Radio Frequency Systems for NMR Imaging: Coil Development and Studies of Non-Thermal Biological Effects

   Författare :Lars Malmgren; Lunds universitet; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; anechoic chamber; TEM transmission cells; FDTD; circularly polarized electromagnetic fields; reduced coupling; noise matching; matching networks; low noise amplifiers; upper thoracic spine; surface coils; Nuclear magnetic resonance; magnetic resonance imaging; non-thermal biological effects; blood-brain barrier; Electronics; Elektronik;

   Sammanfattning : This thesis concerns both design and optimization of NMR imaging systems and studies on non-thermal biological effects of electromagnetic fields. These two research fields are linked together by the fact that humans are subject to static and pulsed magnetic fields as well as to magnetic radio frequency fields (RF) during an NMR imaging investigation. LÄS MER

7. 25. Mathematical Tools Applied in Computational Electromagnetics for a Biomedical Application and Antenna Analysis

   Författare :Farid Monsefi; Sergei Silvestrov; Magnus Otterskog; Linus Carlsson; Jean-Pierre Bérenger; Mälardalens högskola; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Mathematics Applied Mathematics; matematik tillämpad matematik;

   Sammanfattning : To ensure a high level of safety and reliability of electronic/electric systems EMC (electromagnetic compatibility) tests together with computational techniques are used. In this thesis, mathematical modeling and computational electromagnetics are applied to mainly two case studies. LÄS MER