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Modeling and Extrapolating Highfrequency Electromagnetic Currents on Conducting Obstacles
KTH, School of Computer Science and Communication (CSC), Numerical Analysis and Computer Science, NADA.
KTH, School of Computer Science and Communication (CSC), Numerical Analysis and Computer Science, NADA.
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.

Place, publisher, year, edition, pages
2005. 1-4 p.
Keyword [en]
Numerical Methods, Electromagnetics, Method of Moments, Physical Optics, Surface Currents.
National Category
Computational Mathematics
Identifiers
URN: urn:nbn:se:kth:diva-8998OAI: oai:DiVA.org:kth-8998DiVA: diva2:14526
Note
QC 20101004Available from: 2006-01-16 Created: 2006-01-16 Last updated: 2010-10-04Bibliographically approved
In thesis
1. Computational electromagnetics: software development and high frequency modeling of surface currents on perfect conductors
Open this publication in new window or tab >>Computational electromagnetics: software development and high frequency modeling of surface currents on perfect conductors
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
High frequency approximations, Maxwell’s equations, Method of Moments, Physical Optics, Geometrical Theory of Diffraction, Extraction Extrapolation
National Category
Computational Mathematics
Identifiers
urn:nbn:se:kth:diva-590 (URN)91-7178-203-6 (ISBN)
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

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http://www.nada.kth.se/~sandy/RAPPORTS/icnaam2005.pdf

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