| 31. |
- Derneryd, Anders, et al.
(författare)
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Application of gain-bandwidth bounds on loaded dipoles
- 2009
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Ingår i: IET Microwaves, Antennas & Propagation. - : Institution of Engineering and Technology (IET). - 1751-8725. ; 3:6, s. 959-966
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Tidskriftsartikel (refereegranskat)abstract
- Physical limitations based only on antenna volume, form factor and material parameters are applied to electrically small antennas in the form of single dipoles. The upper bound on the gain-bandwidth product is solely determined by the polarisability matrix that characterises the antenna when it is immersed in a uniform applied static field. The polarisability, and hence the bandwidth, is increased by loading the dipole arms close to their ends. The half-power impedance bandwidth is increased from 5 to 13% by moving the coils from the centre to the ends of the dipole arms. The introduction of a stub-matching further improves the bandwidth but the physical limit is not reached. Finally, a dual-resonance dipole antenna is analysed. It is observed that a second resonance hardly reduces the bandwidth of the first resonance if the resonances are separated more than 1.7 times in frequency.
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| 32. |
- Derneryd, Anders, et al.
(författare)
-
Mobile and terminal antennas
- 2003
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Ingår i: Antenn 03. Nordic Antenna Symposium. Conference Proceedings. ; , s. 37-38
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- This project deals with the analysis of antennas for mobiles and terminals in the form of a patch element on a grounded substrate. A special case of this antenna element is the PIFA-element. The analysis is based on the propagator method, a vector generalisation of the transmission line theory, that has been extended to the analysis of surface waves in inhomogeneous permittivity profiles. Analyses of combined antenna radiation pattern and propagation channel characteristics have been initiated in order to demonstrate the performance advantage of exploiting two-antenna signals on a terminal for diversity or interference suppression. A generic two-antenna terminal is presented in this paper which improves capacity on reception. Signal correlation coefficients that depend on the mutual coupling are calculated.
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| 33. |
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| 34. |
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| 35. |
- Derneryd, Anders, et al.
(författare)
-
Signal correlation including antenna coupling
- 2004
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Ingår i: Electronics Letters. - : Institution of Engineering and Technology (IET). - 1350-911X .- 0013-5194. ; 40:3, s. 157-159
-
Tidskriftsartikel (refereegranskat)abstract
- Mutual coupling effects between antenna elements on signal correlation are reported. A simple expression is derived to compute the correlation coefficient from the far-field radiation patterns including the characteristics of the propagation environment and the terminating impedance. It is shown that the mutual coupling between closely spatially separated dipoles call lead to increased signal decorrelation.
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| 36. |
- Egorov, Igor, et al.
(författare)
-
Transient electromagnetic wave propagation in laterally discontinuous, dispersive media
- 2001
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Ingår i: Wave Motion. - 0165-2125. ; 33:1, s. 67-77
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Tidskriftsartikel (refereegranskat)abstract
- This paper concerns propagation of transient electromagnetic waves in laterally discontinuous dispersive media. The approach, used here, employs a component decomposition of all fields. Specifically, the propagation operator that maps a transverse field on one plane to another plane is specified. Expansion of this mapping near the wave front determines the precursor or forerunner of the problem.
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| 37. |
- Egorov, Igor, et al.
(författare)
-
Transient electromagnetic wave propagation in laterally discontinuous, dispersive media
- 1996
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- This paper concerns propagation of transient electromagnetic waves in laterally discontinuous dispersive media. The approach, used here, employs a component decomposition of all fields. Specifically, the propagation operator that maps a transverse field on one plane to another plane is specified. Expansion of this mapping near the wave front determines the precursor or forerunner of the problem.
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| 38. |
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| 39. |
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| 40. |
- Engström, Christian, et al.
(författare)
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Homogenization of the Maxwell equations using Floquet-Bloch decomposition
- 2003
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Ingår i: Mathematical and numerical waves 2003. - Berlin, Heidelberg : Springer. - 9783642558566 - 354040127X ; , s. 412-416
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Konferensbidrag (refereegranskat)abstract
- Using Bloch waves to represent the full solution of the Maxwell equations inperiodic media, we study the limit process where the material's period becomes much smaller than the wavelenght. it is seen that effective material parameters can be extracted and explicity represented in terms of the non-vanishing Bloch waves, providing an alternative means of homogenization.
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