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Computational electromagnetics: software development and high frequency modeling of surface currents on perfect conductors
KTH, School of Computer Science and Communication (CSC), Numerical Analysis and Computer Science, NADA.
2005 (English)Doctoral thesis, comprehensive summary (Other scientific)
Abstract [en]

In high frequency computational electromagnetics, rigorous numerical methods be come unrealistic tools due to computational demand increasing with the frequency. Instead approximations to the solutions of the Maxwell equations can be employed to evaluate th electromagnetic fields.

In this thesis, we present the implementations of three high frequency approximat methods. The first two, namely the Geometrical Theory of Diffraction (GTD) and th Physical Optics (PO), are commonly used approximations. The third is a new invention that will be referred to as the Surface Current Extraction-Extrapolation (SCEE).

Specifically, the GTD solver is a flexible and modular software package which use Non-Uniform Rational B-spline (NURBS) surfaces to model complex geometries.

The PO solver is based on a triangular description of the surfaces and includes fas shadowing by ray tracing as well as contribution from edges to the scattered fields. GTD ray tracing was combined with the PO solver by a well thought-out software architecture Both implementations are now part of the GEMS software suite, the General ElectroMag netic Solvers, which incorporates state-of-the-art numerical methods. During validations both GTD and PO techniques turned out not to be accurate enough to meet the indus trial standards, thus creating the need for a new fast approximate method providing bette control of the approximations.

In the SCEE approach, we construct high frequency approximate surface currents ex trapolated from rigourous Method of Moments (MoM) models at lower frequency. T do so, the low frequency currents are projected onto special basis vectors defined on th surface relative to the direction of the incident magnetic field. In such configuration, w observe that each component displays systematic spatial patterns evolving over frequenc in close correlation with the incident magnetic field, thus allowing us to formulate a fre quency model for each component. This new approach is fast, provides good control of th error and represents a platform for future development of high frequency approximations.

As an application, we have used these tools to analyse the radar detectability of a new marine distress signaling device. The device, called "Rescue-Wing", works as an inflatabl radar reflector designed to provide a strong radar echo useful for detection and positionin during rescue operations of persons missing at sea.

Place, publisher, year, edition, pages
Stockholm: KTH , 2005. , xi, 39 p.
Series
Trita-NA, ISSN 0348-2952 ; 0541
Keyword [en]
High frequency approximations, Maxwell’s equations, Method of Moments, Physical Optics, Geometrical Theory of Diffraction, Extraction Extrapolation
National Category
Computational Mathematics
Identifiers
URN: urn:nbn:se:kth:diva-590ISBN: 91-7178-203-6 (print)OAI: oai:DiVA.org:kth-590DiVA: diva2:14532
Public defence
2006-01-27, Sal D3, Lindstedtsvägen 5, Stockholm, 10:15
Opponent
Supervisors
Note
QC 20101004Available from: 2006-01-16 Created: 2006-01-16 Last updated: 2010-10-04Bibliographically approved
List of papers
1. Modeling and Extrapolating Highfrequency Electromagnetic Currents on Conducting Obstacles
Open this publication in new window or tab >>Modeling and Extrapolating Highfrequency Electromagnetic Currents on Conducting Obstacles
2005 (English)Conference paper, Published paper (Refereed)
Abstract [en]

We present a current-based approach to high frequency approximate techniques in Computational Electromagnetics(CEM). Our goal is to numerically model the behavior of electromagnetic and surface current vectorfields at high frequency, using information extracted from lower frequency solutions.

Keyword
Numerical Methods, Electromagnetics, Method of Moments, Physical Optics, Surface Currents.
National Category
Computational Mathematics
Identifiers
urn:nbn:se:kth:diva-8998 (URN)
Note
QC 20101004Available from: 2006-01-16 Created: 2006-01-16 Last updated: 2010-10-04Bibliographically approved
2. Extrapolation and Modelling of Method of Moments Currents on a PEC surface
Open this publication in new window or tab >>Extrapolation and Modelling of Method of Moments Currents on a PEC surface
2005 (English)In: Mathematical Modeling of Wave Phenomena, 2005, 92-99 p.Conference paper, Published paper (Refereed)
Abstract [en]

We present a current-based approach to high frequency approximation techniques. Our goal is to numerically model the behaviour of electromagnetic and surface current vector fields at medium-range or high frequency, using information extracted from lower frequency solutions.

Series
AIP CONFERENCE PROCEEDINGS, ISSN 0094-243X
Keyword
high frequency approximations, Method of Moments, Physical Optics
National Category
Computational Mathematics
Identifiers
urn:nbn:se:kth:diva-8999 (URN)10.1063/1.2205792 (DOI)000237610000009 ()2-s2.0-33845591539 (Scopus ID)0-7354-0325-2 (ISBN)
Conference
2nd Conference on Mathematical Modeling of Wave Phenomena Växjo, SWEDEN, AUG 14-19, 2005
Note

QC 20141117

Available from: 2006-01-16 Created: 2006-01-16 Last updated: 2014-11-17Bibliographically approved
3. Physical Optics And NURBS for RCS Calculations
Open this publication in new window or tab >>Physical Optics And NURBS for RCS Calculations
2004 (English)Conference paper, Published paper (Refereed)
Abstract [en]

This paper presents a Physical Optics method using an adaptivetriangular subdivision scheme for the surface integral in the computation ofmonostatic RCS of NURBS surfaces.

National Category
Computational Mathematics
Identifiers
urn:nbn:se:kth:diva-9000 (URN)
Conference
Proceedings EMB04 Conference on Computational Electromagnetics - Methods and Applications, Göteborg, Sweden, October 2004.
Note
QC 20101004Available from: 2006-01-16 Created: 2006-01-16 Last updated: 2010-10-04Bibliographically approved
4. The Rescue Wing: Design of a Marine Distress Signaling Device
Open this publication in new window or tab >>The Rescue Wing: Design of a Marine Distress Signaling Device
2005 (English)In: Proceedings of MTS/IEEE OCEANS, 2005, 2005, 1640129- p.Conference paper, Published paper (Refereed)
Abstract [en]

We present a multidisciplinary scientific analysis combining aerodynamics, flight mechanics and electromagnetics aiming at the design of a new marine distress signaling device. We show how computational fluid dynamics (CFD) and computational electromagnetics (CEM) techniques have been used to assist In the design of both the flight characteristics and the radar performance of the device, as well as how its radar signature compares to popular radar reflectors used on yachts and sailboats.

Series
Oceans-IEEE, ISSN 0197-7385
Keyword
Aerodynamics, Computational fluid dynamics, Electromagnetic fields, Flight dynamics, Radar reflection, Radar systems
National Category
Vehicle Engineering
Identifiers
urn:nbn:se:kth:diva-5804 (URN)10.1109/OCEANS.2005.1640129 (DOI)000238978702089 ()2-s2.0-33947221013 (Scopus ID)
Conference
MTS/IEEE OCEANS, 2005; Washington, DC; 18 September 2005 through 23 September 2005
Note
QC 20100910Available from: 2006-05-29 Created: 2006-05-29 Last updated: 2010-10-04Bibliographically approved
5. Modular Approach to GTD in the Context of Solving Large Hybrid Problems
Open this publication in new window or tab >>Modular Approach to GTD in the Context of Solving Large Hybrid Problems
2000 (English)Conference paper, Published paper (Refereed)
National Category
Computational Mathematics
Identifiers
urn:nbn:se:kth:diva-9002 (URN)
Conference
Proceedings OCEANS 2005 Conference on Ocean Science sponsored by the Marine Technology Society (MTS) and the IEEE Oceanic Engineering Society,Washington DC, United States, September 2005.
Note
QC 20101004Available from: 2006-01-16 Created: 2006-01-16 Last updated: 2010-10-04Bibliographically approved
6. Architecture and Geometrical Algorithms in MIRA, a Ray-based Electromagnetic Wave Simulator
Open this publication in new window or tab >>Architecture and Geometrical Algorithms in MIRA, a Ray-based Electromagnetic Wave Simulator
2001 (English)Conference paper, Published paper (Refereed)
Abstract [en]

In this paper we describe the basic architecture of the user-oriented electromagnetic simulator called MIRA which determines the near and far field from transmitting antennas and plane waves. The simulator is a part of the Swedish code development project GEMS: General ElectroMagnetic Solvers supported by PSCI, KTH, Saab Avionics AB, and NFFP and continues in the NFFP 473 project SMART.

Keyword
Design Software, Geometrical Theory of Diffraction, Ray Tracing, Shadow Detection
National Category
Computational Mathematics
Identifiers
urn:nbn:se:kth:diva-9003 (URN)
Conference
Proceedings EMB01 Conference on Computational Electromagnetics - Methods and Applications, Uppsala, Sweden, November 2001.
Note
QC 20101004Available from: 2006-01-16 Created: 2006-01-16 Last updated: 2010-10-04Bibliographically approved

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CiteExportLink to record
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Citation style
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