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State-space models and stored electromagnetic energy for antennas in dispersive and heterogeneous media

Gustafsson, Mats LU and Ehrenborg, Casimir LU (2017) In Radio Science 52(11). p.1325-1343
Abstract

Accurate and efficient evaluation of the stored energy is essential for Q factors, physical bounds, and antenna current optimization. Here it is shown that the stored energy can be estimated from quadratic forms based on a state-space representation derived from the electric and magnetic field integral equations. The derived expressions are valid for small antennas embedded in temporally dispersive and inhomogeneous media. The quadratic forms also provide simple single frequency formulas for the corresponding Q factors. Numerical examples comparing the different Q factors are presented for dipole and meander line antennas in conductive, Debye, and Lorentz media for homogeneous and inhomogeneous media. The computed Q factors are also... (More)

Accurate and efficient evaluation of the stored energy is essential for Q factors, physical bounds, and antenna current optimization. Here it is shown that the stored energy can be estimated from quadratic forms based on a state-space representation derived from the electric and magnetic field integral equations. The derived expressions are valid for small antennas embedded in temporally dispersive and inhomogeneous media. The quadratic forms also provide simple single frequency formulas for the corresponding Q factors. Numerical examples comparing the different Q factors are presented for dipole and meander line antennas in conductive, Debye, and Lorentz media for homogeneous and inhomogeneous media. The computed Q factors are also verified with the Q factor obtained from the stored energy in Brune synthesized circuit models.

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Please use this url to cite or link to this publication:
author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
antennas, dispersion, electromagnetics, Q factor, stored energy
in
Radio Science
volume
52
issue
11
pages
19 pages
publisher
American Geophysical Union
external identifiers
  • scopus:85038213975
  • wos:000418251400002
ISSN
0048-6604
DOI
10.1002/2017RS006281
language
English
LU publication?
yes
id
192a4bf1-af8b-498c-ac55-164b33bd2be0
date added to LUP
2018-01-04 10:56:53
date last changed
2018-04-01 04:37:49
@article{192a4bf1-af8b-498c-ac55-164b33bd2be0,
  abstract     = {<p>Accurate and efficient evaluation of the stored energy is essential for Q factors, physical bounds, and antenna current optimization. Here it is shown that the stored energy can be estimated from quadratic forms based on a state-space representation derived from the electric and magnetic field integral equations. The derived expressions are valid for small antennas embedded in temporally dispersive and inhomogeneous media. The quadratic forms also provide simple single frequency formulas for the corresponding Q factors. Numerical examples comparing the different Q factors are presented for dipole and meander line antennas in conductive, Debye, and Lorentz media for homogeneous and inhomogeneous media. The computed Q factors are also verified with the Q factor obtained from the stored energy in Brune synthesized circuit models.</p>},
  author       = {Gustafsson, Mats and Ehrenborg, Casimir},
  issn         = {0048-6604},
  keyword      = {antennas,dispersion,electromagnetics,Q factor,stored energy},
  language     = {eng},
  month        = {11},
  number       = {11},
  pages        = {1325--1343},
  publisher    = {American Geophysical Union},
  series       = {Radio Science},
  title        = {State-space models and stored electromagnetic energy for antennas in dispersive and heterogeneous media},
  url          = {http://dx.doi.org/10.1002/2017RS006281},
  volume       = {52},
  year         = {2017},
}