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| 2. |
- Alayon Glazunov, Andres, et al.
(författare)
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On the mean effective gain expressed in terms of the spherical vector wave expansion of the electromagnetic field
- 2008
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Konferensbidrag (refereegranskat)abstract
- The mode expansion o®ers a general framework for the analysis of the interaction between antennas andpropagation channels. In this paper, the Mean E®ective Gain (MEG) of an antenna is expressed in termsof the spherical vector wave expansion of the electromagnetic ¯eld. An explicit expression of the MEG isprovided as a function of the normalized average power of modes excited in the propagation channel andthe correlation between the channel modes due to the polarization and spatial selectivity of plane wavesimpinging at the antenna.
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| 3. |
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| 4. |
- Alayon Glazunov, Andres, et al.
(författare)
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Spherical Vector Wave Expansion of Gaussian Electromagnetic Fields for Antenna-Channel Interaction Analysis
- 2009
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Ingår i: IEEE Transactions on Antennas and Propagation. - 0018-926X .- 1558-2221. ; 57:7, s. 2055-2067
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Tidskriftsartikel (refereegranskat)abstract
- In this paper, we introduce an approach to analyze the interaction between antennas and the propagation channel. We study both the antennas and the propagation channel by means of the spherical vector wave mode expansion of the electromagnetic field. Then we use the expansion coefficients to study some properties of general antennas in thosefields by means of the antenna scattering matrix. The focus is on the spatio-polar characterization of antennas, channels and their interactions. We provide closed form expressions for the covariance of the field multimodes as function of the power angle spectrum (PAS) and the channel cross-polarization ratio (XPR). A new interpretation of the mean effective gains (MEG) of antennas is also provided. The maximum MEG is obtained by conjugate mode matching between the antennas and the channel; we also prove the (intuitive) results that the optimum decorrelation of the antenna signals is obtained by the excitation of orthogonal spherical vector modes.
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| 5. |
- Alayon Glazunov, Andres, et al.
(författare)
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Spherical Vector Wave Expansion of Gaussian Electromagnetic Fields for Antenna-Channel Interaction Analysis
- 2008
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- In this paper we introduce an approach to analyze the interaction between antennas and the propagation channel. We study both the antennas and the propagation channel by means of the spherical vector wave mode expansion of the electromagnetic field. Then we use the expansion coefficients to study some properties of general antennas in those fields by means of the antenna scattering matrix. The focus is on the spatio-polar characterization of antennas, channels and their interactions. We provide closed form expressions for the covariance of the field multi-modes as function of the Power Angle Spectrum (PAS) and the channel cross-polarization ratio (XPR). A new interpretation of the Mean Effective Gains (MEG) of antennas is also provided. The maximum MEG is obtained by conjugate mode matching between the antennas and the channel; we also prove the (intuitive) results that the optimum decorrelation of the antenna signals is obtained by the excitation of orthogonal spherical vector modes.
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| 6. |
- Bolin, Thomas, et al.
(författare)
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Two-antenna receive diversity performance in indoor environment
- 2005
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Ingår i: Electronics Letters. - : Institution of Engineering and Technology (IET). - 1350-911X .- 0013-5194. ; 41:22, s. 1205-1206
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Tidskriftsartikel (refereegranskat)abstract
- Receive diversity gain performance of a two-antenna setup in an office environment is reported. The terminal is handheld in front of the user simulating a data mode scenario while walking around. The dual polarised base station sector antenna is placed at the end of a corridor. The results indicate that experimentally achieved diversity performance is similar to previously predicted theoretical data.
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| 8. |
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| 9. |
- 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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| 10. |
- Gustafsson, Mats, et al.
(författare)
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A time-domain approach to the extinction paradox for scattering of electromagnetic waves
- 2008
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Ingår i: ; , s. 1-4
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Konferensbidrag (refereegranskat)abstract
- The extinction paradox states that a perfectly electric conducting target which is large compared to the wavelength removes from the incident radiation exactly twice the amount of power it can intercept by its geometrical cross section area. In this paper, the extinction paradox is generalized to include temporally dispersive material parameters with finite values of the permittivity and the permeability. From a time-domain approach it is shown that the high-frequency limit of the extinction cross section depends on the material parameters of the target and that a limiting value not necessarily exists. These findings are exemplified by several numerical illustrations with different values of the extinction cross section in the high-frequency limit.
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