| 1. |
- Fridén, Jonas, et al.
(författare)
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Calculation of antenna radiation center using angular momentum
- 2013
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Ingår i: IEEE Transactions on Antennas and Propagation. - 0018-926X. ; 61:12, s. 5923-5930
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Tidskriftsartikel (refereegranskat)abstract
- An algorithm to compute the radiation center of an antenna, using the Spherical wave expansion (SWE) of the far field or the far field directly, is introduced. The method is based on the angular momentum that is uniquely defined for any antenna far field pattern. The radiation center is defined as the phase reference point where the angular momentum is minimized and corresponds to minimizing the phase variations in the antenna far field pattern. In addition, this approach also allows for determination of the current distribution axis.
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| 2. |
- Friden, Jonas, et al.
(författare)
-
Calculation of antenna radiation center using angular momentum
- 2012
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- An algorithm to compute the Radiation Center of an antenna based on the Spherical Wave Expansion is introduced. The method is based on the angular momentum vector that is uniquely defined for any antenna far field pattern. The radiation center is defined as the phase reference point where the angular momentum is minimized and corresponds to minimizing the phase variations in the antenna far field pattern. In addition, this approach also allows for determination of the Current Distribution Axis.
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| 3. |
- Fridén, Jonas, et al.
(författare)
-
Calculation of antenna radiation center using angular momentum
- 2013
-
Ingår i: 7th European Conference on Antennas and Propagation (EuCAP), 2013. - 9781467321877 ; , s. 1531-1535
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Konferensbidrag (refereegranskat)abstract
- An algorithm to compute the Radiation center of an antenna based on the Spherical wave expansion is introduced. The method is based on the angular momentum vector that is uniquely defined for any antenna far field pattern. The radiation center is defined as the unique point where the magnitude of the angular momentum is minimized with respect to translations of the far field. This corresponds to minimizing the phase variations in the antenna far field pattern. In addition the Current distribution axis can be determined, corresponding to minimization of the vertical component of angular momentum.
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| 4. |
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| 5. |
- Gustafsson, Mats, et al.
(författare)
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Forward scattering of loaded and unloaded antennas
- 2012
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Ingår i: IEEE Transactions on Antennas and Propagation. - 0018-926X. ; 60:12, s. 5663-5668
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Tidskriftsartikel (refereegranskat)abstract
- Forward scattering of antennas is related to antenna performance via the forward scattering sum rule. The forward scattering sum rule is an integral identity that shows that a weighted integral of the extinction cross section over all spectrum is proportional to the static polarizabiliy of the antenna structure. Here, the forward scattering sum rule is experimentally verified for loaded, short circuit, and open circuit cylindrical dipole antennas. It is also shown that the absorption efficiency cannot be greater than 1/2 for reciprocal linearly polarized lossless matched antennas with a symmetric radiation pattern.
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| 6. |
- Gustafsson, Mats, et al.
(författare)
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Physical bounds on the partial realized gain
- 2010
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Ingår i: [Host publication title missing]. ; , s. 1-6
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Konferensbidrag (refereegranskat)abstract
- An antenna identity, derived from the forward scattering sum rule, shows that the partial realized gain of an antenna is related to the polarizability of the antenna structure. The partial realized gain contains the mismatch, directivity, efficiency, and polarization properties of the antenna. The antenna identity expresses how the performance depends on the electrical size and shape of the antenna structure. It is also the starting point for several antenna bounds. In this paper, the identity, its associated physical bounds, and computational aspects of the polarizability dyadics are discussed.
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| 7. |
- Gustafsson, Mats, et al.
(författare)
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Sum rules and physical bounds in electromagnetic theory
- 2010
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Ingår i: [Host publication title missing]. ; , s. 37-40
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Konferensbidrag (refereegranskat)abstract
- Sum rules are useful in many branches of physics and engineering as they relate all spectrum parameter values with their asymptotic expansions. Properties of the dynamic response can hence be inferred by the, in many cases much simpler, static response. This has e.g., been used for lossless matching networks, radar absorbers, extinction cross section, partial realized gain of antennas, high-impedance surfaces, transmission cross section, transmission coefficients, and temporal dispersion of metamaterials. Here, several sum rules and their associated physical bounds are reviewed and it is shown that integral identities for Herglotz functions offer a unified approach in deriving them.
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| 8. |
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| 9. |
- Ioannidis, Andreas, et al.
(författare)
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On the Well-Posedness of the Maxwell System for Linear Bianisotropic Media
- 2012
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Ingår i: SIAM Journal on Mathematical Analysis. - : Society for Industrial & Applied Mathematics (SIAM). - 0036-1410 .- 1095-7154. ; 44:4, s. 2459-2473
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Tidskriftsartikel (refereegranskat)abstract
- The time-dependent Maxwell system is supplemented with the constitutive relations of linear bianisotropic media and is treated as a neutral integro-differential equation in a Hilbert space. By using the theory of abstract Volterra equations and strongly continuous semigroups we obtain general well-posedness results for the corresponding mathematical problem.
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| 10. |
- Ioannidis, Andreas, et al.
(författare)
-
On the well-posedness of the Maxwell system for linear bianisotropic media
- 2010
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- The time dependent Maxwell system is supplemented with the constitutive relations of linear bianisotropc media and is treated as a neutral integro-differential equation in a Hilbert space. By using the theory of abstract Volterra equations and strongly continuous semigroups we obtain general well-posedness results for the corresponding mathematical problem.
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