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Maximum gain, effective area, and directivity

Gustafsson, Mats LU and Capek, Miloslav (2019) In IEEE Transactions on Antennas and Propagation 67(8). p.5282-5293
Abstract

Fundamental bounds on antenna gain are found via convex optimization of the current density in a prescribed region. Various constraints are considered, including self-resonance and only partial control of the current distribution. Derived formulas are valid for arbitrarily shaped radiators of a given conductivity. All the optimization tasks are reduced to eigenvalue problems, which are solved efficiently. The second part of this paper deals with superdirectivity and its associated minimal costs in efficiency and Q-factor. This paper is accompanied by a series of examples practically demonstrating the relevance of the theoretical framework and entirely spanning a wide range of material parameters and electrical sizes used in antenna... (More)

Fundamental bounds on antenna gain are found via convex optimization of the current density in a prescribed region. Various constraints are considered, including self-resonance and only partial control of the current distribution. Derived formulas are valid for arbitrarily shaped radiators of a given conductivity. All the optimization tasks are reduced to eigenvalue problems, which are solved efficiently. The second part of this paper deals with superdirectivity and its associated minimal costs in efficiency and Q-factor. This paper is accompanied by a series of examples practically demonstrating the relevance of the theoretical framework and entirely spanning a wide range of material parameters and electrical sizes used in antenna technology. The presented results are analyzed from a perspective of effectively radiating modes. In contrast to a common approach utilizing spherical modes, the radiating modes of a given body are directly evaluated and analyzed here. All crucial mathematical steps are reviewed in the appendices, including a series of important subroutines to be considered making it possible to reduce the computational burden associated with the evaluation of electrically large structures and structures of high conductivity.

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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Antenna gain, antenna theory, current distribution, directivity, eigenvalues and eigenfunctions, optimization methods, radiation efficiency
in
IEEE Transactions on Antennas and Propagation
volume
67
issue
8
pages
12 pages
publisher
IEEE--Institute of Electrical and Electronics Engineers Inc.
external identifiers
  • scopus:85070596521
ISSN
0018-926X
DOI
10.1109/TAP.2019.2916760
language
English
LU publication?
yes
id
c537b620-f061-49ec-873a-ce9e56886878
date added to LUP
2019-09-03 12:54:13
date last changed
2019-09-17 04:59:53
@article{c537b620-f061-49ec-873a-ce9e56886878,
  abstract     = {<p>Fundamental bounds on antenna gain are found via convex optimization of the current density in a prescribed region. Various constraints are considered, including self-resonance and only partial control of the current distribution. Derived formulas are valid for arbitrarily shaped radiators of a given conductivity. All the optimization tasks are reduced to eigenvalue problems, which are solved efficiently. The second part of this paper deals with superdirectivity and its associated minimal costs in efficiency and Q-factor. This paper is accompanied by a series of examples practically demonstrating the relevance of the theoretical framework and entirely spanning a wide range of material parameters and electrical sizes used in antenna technology. The presented results are analyzed from a perspective of effectively radiating modes. In contrast to a common approach utilizing spherical modes, the radiating modes of a given body are directly evaluated and analyzed here. All crucial mathematical steps are reviewed in the appendices, including a series of important subroutines to be considered making it possible to reduce the computational burden associated with the evaluation of electrically large structures and structures of high conductivity.</p>},
  articleno    = {8718501},
  author       = {Gustafsson, Mats and Capek, Miloslav},
  issn         = {0018-926X},
  keyword      = {Antenna gain,antenna theory,current distribution,directivity,eigenvalues and eigenfunctions,optimization methods,radiation efficiency},
  language     = {eng},
  number       = {8},
  pages        = {5282--5293},
  publisher    = {IEEE--Institute of Electrical and Electronics Engineers Inc.},
  series       = {IEEE Transactions on Antennas and Propagation},
  title        = {Maximum gain, effective area, and directivity},
  url          = {http://dx.doi.org/10.1109/TAP.2019.2916760},
  volume       = {67},
  year         = {2019},
}