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| 2. |
- Gustafsson, Mats, et al.
(författare)
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An overview of some recent physical bounds in scattering and antenna theory
- 2009
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Ingår i: ; , s. 1715-1718
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Konferensbidrag (refereegranskat)abstract
- The objective of this paper is to give an overview of some recently developed sum rules and physical bounds in scattering and antenna theory. The sum rules are based on integral identities for Herglotz functions that relate the quantity of interest with its low and high-frequency behavior. The sum rules are transformed to bounds by estimating the integrals and applying variational results to the parameters that appear in the asymptotic expansions. The theoretical findings are exemplified by numerical results for various scattering and antenna configurations.
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| 3. |
- Gustafsson, Mats, et al.
(författare)
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Physical bounds and sum rules in scattering and antenna theory
- 2009
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Ingår i: Electromagnetics in Advanced Applications, 2009. ICEAA '09. International Conference on. ; , s. 600-603, s. 600-603
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Konferensbidrag (refereegranskat)abstract
- The objective of this paper is to review some recently developed sum rules and physical bounds in scattering and antenna theory. The sum rules are based on identities for Herglotz functions that relate the quantity of interest integrated over all wavelengths with its static polarizability dyadics. They are transformed to physical bounds by applying variational principles for the polarizability dyadics together with various estimates of the integrals. The theoretical findings are exemplified by numerical results for several configurations.
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| 4. |
- 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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| 5. |
- 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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| 6. |
- Nordebo, Sven, et al.
(författare)
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On the relation between optimal wideband matching and scattering of spherical waves
- 2011
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Ingår i: IEEE Transactions on Antennas and Propagation. - 0018-926X .- 1558-2221. ; 59:9, s. 3358-3369
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Tidskriftsartikel (refereegranskat)abstract
- Abstract in UndeterminedUsing an exact circuit analogy for the scattering ofvector spherical waves, it is shown how the problem of determiningthe optimal scattering bounds for a homogeneous spherein its high-contrast limit is identical to the closely related, andyet very different problem of finding the broadband tuning limitsof the spherical waves. Using integral relations similar to Fano’sbroadband matching bounds, the optimal scattering limitationsare determined by the static response as well as the high-frequencyasymptotics of the reflection coefficient. The scattering view of thematching problem yields explicitly the necessary low-frequencyasymptotics of the reflection coefficient that is used with Fano’sbroadband matching bounds for spherical waves, something thatappears to be non-trivial to derive from the classical networkpoint of view.
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| 7. |
- Nordebo, Sven, et al.
(författare)
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On the relation between optimal wideband matching and scattering of spherical waves
- 2010
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Using an exact circuit analogy for the scattering of vector spherical waves, it is shown how the problem of determining the optimal scattering bounds for a homogeneous sphere in its high-contrast limit is identical to the closely related, and yet very different problem of finding the broadband tuning limits of the spherical waves. Using integral relations similar to Fano's broadband matching bounds, the optimal scattering limitations are determined by the static response as well as the high-frequency asymptotics of the reflection coefficient. The scattering view of the matching problem yields explicitly the necessary low-frequency asymptotics of the reflection coefficient that is used with Fano's broadband matching bounds for spherical waves, something that appears to be non-trivial to derive from the classical network point of view.
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