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Transient electromagnetic pulse propagation in temporally dispersive materials

Egorov, Igor LU (1998)
Abstract (Swedish)
Popular Abstract in Swedish

Avhandlingen behandlar elektromagnetisk vågutbredning i dispersiva material. Ett material är dispersivt om vågor med olika frekvenser propagerar genom det med olika hastigheter, dvs om materialparametrar är frekvensberoende. Pulsutbredning i dispersiva media karakteriseras av att pulsens form ändras under utbredning genom materialet. Traditionellt behandlas vågutbredningsproblem i frekvensdomänen, dvs man delar upp infallande vågen i monokromatiska vågor med hjälp av fouriertransformation, man propagerar sedan varje sådan in i materialet och till slut kombinerar man dem med hjälp av invers fouriertransformation för att få den resulterande signalen. I denna avhandling är analysen utförd i... (More)
Popular Abstract in Swedish

Avhandlingen behandlar elektromagnetisk vågutbredning i dispersiva material. Ett material är dispersivt om vågor med olika frekvenser propagerar genom det med olika hastigheter, dvs om materialparametrar är frekvensberoende. Pulsutbredning i dispersiva media karakteriseras av att pulsens form ändras under utbredning genom materialet. Traditionellt behandlas vågutbredningsproblem i frekvensdomänen, dvs man delar upp infallande vågen i monokromatiska vågor med hjälp av fouriertransformation, man propagerar sedan varje sådan in i materialet och till slut kombinerar man dem med hjälp av invers fouriertransformation för att få den resulterande signalen. I denna avhandling är analysen utförd i tidsdomänen, dvs inga f ouriertransformationer är involverade. Vågutbredning i både enkla (isotropa) och mer komplicerade (bi-isotropa, anisotropa) material är behandlade. Vågens beteende i en omgivning av vågfronten har speciellt undersökts. I en stor klass av dispersiva material föregås ankommande huvudsignal av karakteristiska fält - så kallade förlöpare. I denna avhandling har approximationer, uttryckta i speciella funktioner, till första och andra förlöparna erhållits. Även ytintegralekvationer för elektromagnetiska fält är härledda i avhandlingen. De kan vara till hjälp vid lösning av tredimensionella spridningsproblem. En del resultat som kan användas vid analys av pulsutbredning i optiska fibrer har också erhållits. (Less)
Abstract
This thesis treats the problem of transient electromagnetic pulse propagation in temporally dispersive media. The analysis is performed using time-domain techniques. In particular, the dispersive wave splitting which decouples the Maxwell equations both in vacuum and inside the medium is utilized. Complex time-dependent electromagnetic fields are introduced. These fields simplify the Maxwell equations to a compact form suitable for an application of time-domain methods.



Special attention is paid to the precursors (or forerunners). The presence of forerunners is a characteristic property of pulse propagation in temporally dispersive media. The first (Sommerfeld) and the second (Brillouin) precursors are analyzed in a... (More)
This thesis treats the problem of transient electromagnetic pulse propagation in temporally dispersive media. The analysis is performed using time-domain techniques. In particular, the dispersive wave splitting which decouples the Maxwell equations both in vacuum and inside the medium is utilized. Complex time-dependent electromagnetic fields are introduced. These fields simplify the Maxwell equations to a compact form suitable for an application of time-domain methods.



Special attention is paid to the precursors (or forerunners). The presence of forerunners is a characteristic property of pulse propagation in temporally dispersive media. The first (Sommerfeld) and the second (Brillouin) precursors are analyzed in a large class of complex media. The approximations to the first forerunner are obtained in terms of the Bessel functions. The second forerunner approximations are expressed in terms of the hyper-Airy functions. The second forerunner in reflection and transmission data for an isotropic slab is analyzed. Synthetic reflection and transmission data are used to reconstruct the first three susceptibility moments of the material of the slab. Numerical examples confirming the theoretical results are presented.



Time-domain fundamental solutions and Green dyadics for temporally dispersive, simple (linear, homogeneous, and isotropic) or bi-isotropic media are introduced. Surface integral representations of the electromagnetic fields in such media are obtained and used to derive surface integral equations.



A part of the thesis deals with the propagation of transient pulses in laterally discontinuous dispersive media. A system of coupled integro-differential equations for the propagator kernels is derived. (Less)
Please use this url to cite or link to this publication:
author
opponent
  • Prof Ström, Staffan, Royal Institute of Technology, Stockholm, SWEDEN
organization
publishing date
type
Thesis
publication status
published
subject
keywords
Green functions, direct scattering, time domain, wave propagation, bi-gyrotropic, chiral, bi-isotropic, Forerunner, precursor, Green dyadics, Electronics and Electrical technology, Elektronik och elektroteknik
pages
160 pages
publisher
Department of Electromagnetic Theory, Lund Institute of Technology
defense location
Lund Institute of Technology, building E, auditorium E:1406
defense date
1998-05-20 10:15
external identifiers
  • Other:ISRN: LUTEDX/(TEAT-1011)/1-28/(1998)
language
English
LU publication?
yes
id
6eefe2aa-fd46-41d1-8a25-5e1e837ffd23 (old id 38675)
date added to LUP
2007-06-21 09:58:32
date last changed
2016-09-19 08:45:08
@misc{6eefe2aa-fd46-41d1-8a25-5e1e837ffd23,
  abstract     = {This thesis treats the problem of transient electromagnetic pulse propagation in temporally dispersive media. The analysis is performed using time-domain techniques. In particular, the dispersive wave splitting which decouples the Maxwell equations both in vacuum and inside the medium is utilized. Complex time-dependent electromagnetic fields are introduced. These fields simplify the Maxwell equations to a compact form suitable for an application of time-domain methods.<br/><br>
<br/><br>
Special attention is paid to the precursors (or forerunners). The presence of forerunners is a characteristic property of pulse propagation in temporally dispersive media. The first (Sommerfeld) and the second (Brillouin) precursors are analyzed in a large class of complex media. The approximations to the first forerunner are obtained in terms of the Bessel functions. The second forerunner approximations are expressed in terms of the hyper-Airy functions. The second forerunner in reflection and transmission data for an isotropic slab is analyzed. Synthetic reflection and transmission data are used to reconstruct the first three susceptibility moments of the material of the slab. Numerical examples confirming the theoretical results are presented.<br/><br>
<br/><br>
Time-domain fundamental solutions and Green dyadics for temporally dispersive, simple (linear, homogeneous, and isotropic) or bi-isotropic media are introduced. Surface integral representations of the electromagnetic fields in such media are obtained and used to derive surface integral equations.<br/><br>
<br/><br>
A part of the thesis deals with the propagation of transient pulses in laterally discontinuous dispersive media. A system of coupled integro-differential equations for the propagator kernels is derived.},
  author       = {Egorov, Igor},
  keyword      = {Green functions,direct scattering,time domain,wave propagation,bi-gyrotropic,chiral,bi-isotropic,Forerunner,precursor,Green dyadics,Electronics and Electrical technology,Elektronik och elektroteknik},
  language     = {eng},
  pages        = {160},
  publisher    = {ARRAY(0x7e26410)},
  title        = {Transient electromagnetic pulse propagation in temporally dispersive materials},
  year         = {1998},
}