On the analysis of modes in a closed electromagnetic waveguide

Modal expansions are useful to understand wave propagation in an infinite closed electromagnetic waveguide. They can also be used to construct generalized Dirichlet-to-Neumann maps that provide artificial boundary conditions for truncating a computational domain when discretizing the field by finite...

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Main Authors: Halla, Martin, Monk, Peter
Format: Article
Language:English
Published: Académie des sciences 2024-05-01
Series:Comptes Rendus. Mathématique
Online Access:https://comptes-rendus.academie-sciences.fr/mathematique/articles/10.5802/crmath.516/
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author Halla, Martin
Monk, Peter
author_facet Halla, Martin
Monk, Peter
author_sort Halla, Martin
collection DOAJ
description Modal expansions are useful to understand wave propagation in an infinite closed electromagnetic waveguide. They can also be used to construct generalized Dirichlet-to-Neumann maps that provide artificial boundary conditions for truncating a computational domain when discretizing the field by finite elements. The modes of a waveguide arise as eigenfunctions of a non-symmetric eigenvalue problem, and the eigenvalues determine the propagation (or decay) of the modes along the waveguide. For the successful use of waveguide modes, it is necessary to know that the modes exist and form a dense set in a suitable function space containing the trace of the electric field in the waveguide. This paper is devoted to proving such a density result using the methods of Keldysh. We also show that the modes satisfy a useful orthogonality property, and show how the Dirichlet-to-Neumann map can be calculated. Our existence and density results are proved under realistic regularity assumptions on the cross section of the waveguide, and the electromagnetic properties of the materials in the waveguide, so generalizing existing results.
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spelling doaj-art-9f4a253bd61845acbb4e5879fc505cb92025-02-07T11:21:11ZengAcadémie des sciencesComptes Rendus. Mathématique1778-35692024-05-01362G546947910.5802/crmath.51610.5802/crmath.516On the analysis of modes in a closed electromagnetic waveguideHalla, Martin0https://orcid.org/0000-0002-3010-3540Monk, Peter1https://orcid.org/0000-0003-4637-3059Institut für Numerische und Angewandte Mathematik, Georg-Augst Universität Göttingen, Lotzestr. 16-18, 37083 Göttingen, Deutschland.Department of Mathematical Sciences University of Delaware, Newark DE 19716, USA.Modal expansions are useful to understand wave propagation in an infinite closed electromagnetic waveguide. They can also be used to construct generalized Dirichlet-to-Neumann maps that provide artificial boundary conditions for truncating a computational domain when discretizing the field by finite elements. The modes of a waveguide arise as eigenfunctions of a non-symmetric eigenvalue problem, and the eigenvalues determine the propagation (or decay) of the modes along the waveguide. For the successful use of waveguide modes, it is necessary to know that the modes exist and form a dense set in a suitable function space containing the trace of the electric field in the waveguide. This paper is devoted to proving such a density result using the methods of Keldysh. We also show that the modes satisfy a useful orthogonality property, and show how the Dirichlet-to-Neumann map can be calculated. Our existence and density results are proved under realistic regularity assumptions on the cross section of the waveguide, and the electromagnetic properties of the materials in the waveguide, so generalizing existing results.https://comptes-rendus.academie-sciences.fr/mathematique/articles/10.5802/crmath.516/
spellingShingle Halla, Martin
Monk, Peter
On the analysis of modes in a closed electromagnetic waveguide
Comptes Rendus. Mathématique
title On the analysis of modes in a closed electromagnetic waveguide
title_full On the analysis of modes in a closed electromagnetic waveguide
title_fullStr On the analysis of modes in a closed electromagnetic waveguide
title_full_unstemmed On the analysis of modes in a closed electromagnetic waveguide
title_short On the analysis of modes in a closed electromagnetic waveguide
title_sort on the analysis of modes in a closed electromagnetic waveguide
url https://comptes-rendus.academie-sciences.fr/mathematique/articles/10.5802/crmath.516/
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