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Trade-off Between Antenna Efficiency and Q-Factor

Gustafsson, Mats LU ; Capek, Miloslav LU and Schab, Kurt LU (2019) In IEEE Transactions on Antennas and Propagation
Abstract

The trade-off between radiation efficiency and antenna bandwidth, expressed in terms of Q-factor, for small antennas is formulated as a multi-objective optimization problem in current distributions of predefined support. Variants on the problem are constructed to demonstrate the consequences of requiring a self-resonant current as opposed to one tuned by an external reactance. The trade-offs are evaluated for sample problems and the resulting Pareto-optimal sets reveal the relative cost of valuing low radiation Q-factor over high efficiency, the cost in efficiency to require a self-resonant current, the effects of lossy parasitic loading, and other insights. Observations are drawn from the sample problems selected, though the tradeoff... (More)

The trade-off between radiation efficiency and antenna bandwidth, expressed in terms of Q-factor, for small antennas is formulated as a multi-objective optimization problem in current distributions of predefined support. Variants on the problem are constructed to demonstrate the consequences of requiring a self-resonant current as opposed to one tuned by an external reactance. The trade-offs are evaluated for sample problems and the resulting Pareto-optimal sets reveal the relative cost of valuing low radiation Q-factor over high efficiency, the cost in efficiency to require a self-resonant current, the effects of lossy parasitic loading, and other insights. Observations are drawn from the sample problems selected, though the tradeoff evaluation method is valid for studying arbitrary antenna geometries. In the examples considered here, we observe that small increases in Q-factor away from its lower bound allow for dramatic increases in efficiency toward its upper bound.

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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
epub
subject
keywords
Antenna theory, Antennas, Bandwidth, Conductivity, Current distribution, current distribution, eigenvalues and eigenfunctions, Method of moments, Optimization, optimization methods, Q-factor, radiation efficiency
in
IEEE Transactions on Antennas and Propagation
publisher
IEEE--Institute of Electrical and Electronics Engineers Inc.
external identifiers
  • scopus:85059804840
ISSN
0018-926X
DOI
10.1109/TAP.2019.2891448
language
English
LU publication?
yes
id
e0be02a6-b045-4541-af5a-e8ee90b96a71
date added to LUP
2019-01-24 10:50:18
date last changed
2019-02-20 11:44:28
@article{e0be02a6-b045-4541-af5a-e8ee90b96a71,
  abstract     = {<p>The trade-off between radiation efficiency and antenna bandwidth, expressed in terms of Q-factor, for small antennas is formulated as a multi-objective optimization problem in current distributions of predefined support. Variants on the problem are constructed to demonstrate the consequences of requiring a self-resonant current as opposed to one tuned by an external reactance. The trade-offs are evaluated for sample problems and the resulting Pareto-optimal sets reveal the relative cost of valuing low radiation Q-factor over high efficiency, the cost in efficiency to require a self-resonant current, the effects of lossy parasitic loading, and other insights. Observations are drawn from the sample problems selected, though the tradeoff evaluation method is valid for studying arbitrary antenna geometries. In the examples considered here, we observe that small increases in Q-factor away from its lower bound allow for dramatic increases in efficiency toward its upper bound.</p>},
  author       = {Gustafsson, Mats and Capek, Miloslav and Schab, Kurt},
  issn         = {0018-926X},
  keyword      = {Antenna theory,Antennas,Bandwidth,Conductivity,Current distribution,current distribution,eigenvalues and eigenfunctions,Method of moments,Optimization,optimization methods,Q-factor,radiation efficiency},
  language     = {eng},
  month        = {01},
  publisher    = {IEEE--Institute of Electrical and Electronics Engineers Inc.},
  series       = {IEEE Transactions on Antennas and Propagation},
  title        = {Trade-off Between Antenna Efficiency and Q-Factor},
  url          = {http://dx.doi.org/10.1109/TAP.2019.2891448},
  year         = {2019},
}