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Physical Bounds and Optimal Currents on Antennas

Gustafsson, Mats LU ; Cismasu, Marius LU and Jonsson, Lars (2011) In Technical Report LUTEDX/(TEAT-7210)/1-22/(2011) TEAT-7210.
Abstract
Physical bounds on the directivity Q-factor quotient and optimal current distributions are determined for antennas of arbitrary shape and size using an optimization formulation. A variational approach offers closed form solutions for small antennas expressed in the polarizability of the antenna structure. Finite sized antennas are solved using Lagrangian parameters in a method of moments formulation. It is also shown that the considered stored electric energy can be negative for electrically large objects. This effect is mitigated by a Helmholtz decomposition of the current density. Moreover, it is shown that the optimal charge density for a small antenna can be generated by several current densities. Numerical examples for small and large... (More)
Physical bounds on the directivity Q-factor quotient and optimal current distributions are determined for antennas of arbitrary shape and size using an optimization formulation. A variational approach offers closed form solutions for small antennas expressed in the polarizability of the antenna structure. Finite sized antennas are solved using Lagrangian parameters in a method of moments formulation. It is also shown that the considered stored electric energy can be negative for electrically large objects. This effect is mitigated by a Helmholtz decomposition of the current density. Moreover, it is shown that the optimal charge density for a small antenna can be generated by several current densities. Numerical examples for small and large antennas are used to illustrate the results. (Less)
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organization
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type
Book/Report
publication status
published
subject
in
Technical Report LUTEDX/(TEAT-7210)/1-22/(2011)
volume
TEAT-7210
pages
22 pages
publisher
[Publisher information missing]
language
English
LU publication?
yes
id
a05ebddf-fa14-49e8-b05b-abf427af2624 (old id 2004199)
date added to LUP
2011-06-29 08:24:21
date last changed
2016-10-07 15:09:48
@techreport{a05ebddf-fa14-49e8-b05b-abf427af2624,
  abstract     = {Physical bounds on the directivity Q-factor quotient and optimal current distributions are determined for antennas of arbitrary shape and size using an optimization formulation. A variational approach offers closed form solutions for small antennas expressed in the polarizability of the antenna structure. Finite sized antennas are solved using Lagrangian parameters in a method of moments formulation. It is also shown that the considered stored electric energy can be negative for electrically large objects. This effect is mitigated by a Helmholtz decomposition of the current density. Moreover, it is shown that the optimal charge density for a small antenna can be generated by several current densities. Numerical examples for small and large antennas are used to illustrate the results.},
  author       = {Gustafsson, Mats and Cismasu, Marius and Jonsson, Lars},
  institution  = {[Publisher information missing]},
  language     = {eng},
  pages        = {22},
  series       = {Technical Report LUTEDX/(TEAT-7210)/1-22/(2011)},
  title        = {Physical Bounds and Optimal Currents on Antennas},
  volume       = {TEAT-7210},
  year         = {2011},
}