Capacity Bounds and Degrees of Freedom for MIMO Antennas
Ehrenborg, Casimir LU
; Gustafsson, Mats
LU
and Capek, Miloslav
LU
(2021)
In IEEE Transactions on Antennas and Propagation
69(9).
p.5388-5400
- Abstract
The optimal spectral efficiency and number of independent channels for MIMO antennas in isotropic multipath channels are investigated when bandwidth requirements are placed on the antenna. By posing the problem as a convex optimization problem restricted by the port Q-factor a semi-analytical expression is formed for its solution. The antennas are simulated by method of moments and the solution is formulated both for structures fed by discrete ports, as well as for design regions characterized by an equivalent current. It is shown that the solution is solely dependent on the eigenvalues of the so-called energy modes of the antenna. The magnitude of these eigenvalues is analyzed for a linear dipole array as well as a plate with embedded... (More)
The optimal spectral efficiency and number of independent channels for MIMO antennas in isotropic multipath channels are investigated when bandwidth requirements are placed on the antenna. By posing the problem as a convex optimization problem restricted by the port Q-factor a semi-analytical expression is formed for its solution. The antennas are simulated by method of moments and the solution is formulated both for structures fed by discrete ports, as well as for design regions characterized by an equivalent current. It is shown that the solution is solely dependent on the eigenvalues of the so-called energy modes of the antenna. The magnitude of these eigenvalues is analyzed for a linear dipole array as well as a plate with embedded antenna regions. The energy modes are also compared to the characteristic modes to validate characteristic modes as a design strategy for MIMO antennas. The antenna performance is illustrated through spectral efficiency over the Q-factor, a quantity that is connected to the capacity. It is proposed that the number of energy modes below a given Q-factor can be used to estimate the degrees of freedom for that Q-factor.
(Less)
- author
- Ehrenborg, Casimir
LU
; Gustafsson, Mats
LU
and Capek, Miloslav
LU
- organization
- publishing date
- 2021
- type
- Contribution to journal
- publication status
- published
- subject
- keywords
- antenna theory, computational electromagnetics, degrees of freedom, eigenvalues and eigenfunctions, MIMO communication, optimization
- in
- IEEE Transactions on Antennas and Propagation
- volume
- 69
- issue
- 9
- pages
- 13 pages
- publisher
- IEEE - Institute of Electrical and Electronics Engineers Inc.
- external identifiers
-
- scopus:85104184413
- ISSN
- 0018-926X
- DOI
- 10.1109/TAP.2021.3069432
- language
- English
- LU publication?
- yes
- id
- a70426c4-9a8f-48c6-b4dc-67108f13cb27
- date added to LUP
- 2021-04-27 09:20:10
- date last changed
- 2024-03-05 10:39:04
@article{a70426c4-9a8f-48c6-b4dc-67108f13cb27,
abstract = {{<p>The optimal spectral efficiency and number of independent channels for MIMO antennas in isotropic multipath channels are investigated when bandwidth requirements are placed on the antenna. By posing the problem as a convex optimization problem restricted by the port Q-factor a semi-analytical expression is formed for its solution. The antennas are simulated by method of moments and the solution is formulated both for structures fed by discrete ports, as well as for design regions characterized by an equivalent current. It is shown that the solution is solely dependent on the eigenvalues of the so-called energy modes of the antenna. The magnitude of these eigenvalues is analyzed for a linear dipole array as well as a plate with embedded antenna regions. The energy modes are also compared to the characteristic modes to validate characteristic modes as a design strategy for MIMO antennas. The antenna performance is illustrated through spectral efficiency over the Q-factor, a quantity that is connected to the capacity. It is proposed that the number of energy modes below a given Q-factor can be used to estimate the degrees of freedom for that Q-factor.</p>}},
author = {{Ehrenborg, Casimir and Gustafsson, Mats and Capek, Miloslav}},
issn = {{0018-926X}},
keywords = {{antenna theory; computational electromagnetics; degrees of freedom; eigenvalues and eigenfunctions; MIMO communication; optimization}},
language = {{eng}},
number = {{9}},
pages = {{5388--5400}},
publisher = {{IEEE - Institute of Electrical and Electronics Engineers Inc.}},
series = {{IEEE Transactions on Antennas and Propagation}},
title = {{Capacity Bounds and Degrees of Freedom for MIMO Antennas}},
url = {{http://dx.doi.org/10.1109/TAP.2021.3069432}},
doi = {{10.1109/TAP.2021.3069432}},
volume = {{69}},
year = {{2021}},
}