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Bandwidth, Q factor, and resonance models of antennas

Gustafsson, Mats LU orcid and Nordebo, Sven (2006) In Progress in Electromagnetics Research-Pier 62. p.1-20
Abstract
In this paper, we introduce a first order accurate resonance model based on a second order Pade approximation of the reflection coefficient of a narrowband antenna. The resonance model is characterized by its Q factor, given by the frequency derivative of the reflection coefficient. The Bode-Fano matching theory is used to determine the bandwidth of the resonance model and it is shown that it also determines the bandwidth of the antenna for sufficiently narrow bandwidths. The bandwidth is expressed in the Q factor of the resonance model and the threshold limit on the reflection coefficient. Spherical vector modes are used to illustrate the results. Finally, we demonstrate the fundamental difficulty of finding a simple relation between the... (More)
In this paper, we introduce a first order accurate resonance model based on a second order Pade approximation of the reflection coefficient of a narrowband antenna. The resonance model is characterized by its Q factor, given by the frequency derivative of the reflection coefficient. The Bode-Fano matching theory is used to determine the bandwidth of the resonance model and it is shown that it also determines the bandwidth of the antenna for sufficiently narrow bandwidths. The bandwidth is expressed in the Q factor of the resonance model and the threshold limit on the reflection coefficient. Spherical vector modes are used to illustrate the results. Finally, we demonstrate the fundamental difficulty of finding a simple relation between the Q of the resonance model, and the classical Q defined as the quotient between the stored and radiated energies, even though there is usually a close resemblance between these entities for many real antennas. (Less)
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author
and
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Progress in Electromagnetics Research-Pier
volume
62
pages
1 - 20
publisher
EMW Publishing
external identifiers
  • wos:000239815600001
  • scopus:33947245103
ISSN
1070-4698
DOI
10.2528/PIER06033003
language
English
LU publication?
yes
id
a2a792ae-b1e1-4723-b362-00c50a782380 (old id 395462)
date added to LUP
2016-04-01 11:48:54
date last changed
2021-10-06 02:40:31
@article{a2a792ae-b1e1-4723-b362-00c50a782380,
  abstract     = {In this paper, we introduce a first order accurate resonance model based on a second order Pade approximation of the reflection coefficient of a narrowband antenna. The resonance model is characterized by its Q factor, given by the frequency derivative of the reflection coefficient. The Bode-Fano matching theory is used to determine the bandwidth of the resonance model and it is shown that it also determines the bandwidth of the antenna for sufficiently narrow bandwidths. The bandwidth is expressed in the Q factor of the resonance model and the threshold limit on the reflection coefficient. Spherical vector modes are used to illustrate the results. Finally, we demonstrate the fundamental difficulty of finding a simple relation between the Q of the resonance model, and the classical Q defined as the quotient between the stored and radiated energies, even though there is usually a close resemblance between these entities for many real antennas.},
  author       = {Gustafsson, Mats and Nordebo, Sven},
  issn         = {1070-4698},
  language     = {eng},
  pages        = {1--20},
  publisher    = {EMW Publishing},
  series       = {Progress in Electromagnetics Research-Pier},
  title        = {Bandwidth, Q factor, and resonance models of antennas},
  url          = {http://dx.doi.org/10.2528/PIER06033003},
  doi          = {10.2528/PIER06033003},
  volume       = {62},
  year         = {2006},
}