| 1. |
- Al-Rawi, Ali, 1985, et al.
(författare)
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A new compact wideband MIMO antenna – the double-sided tapered self-grounded monopole array
- 2014
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Ingår i: IEEE Transactions on Antennas and Propagation. - 0018-926X .- 1558-2221. ; 62:6, s. 3365 - 3369
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Tidskriftsartikel (refereegranskat)abstract
- We present a new compact wideband multiple input multiple output (MIMO) antenna—the double-sided 4-port arm-tapered self-grounded monopole array, briefly referred to as the butterfly antenna, in the communication. The antenna is very compact with low correlation between ports and high diversity gain. The genetic algorithm optimization scheme has been employed in the design. Simulation results have been verified against measurements. The measured reflection coefficients at all ports are below -7 dB over 0.5–9 GHz and below -4.5 dB over 0.4–0.5 GHz and 9–15 GHz. The measured correlation coefficients are below 0.4 over 0.4–15 GHz and lower than 0.1 in most of the frequency band. This new MIMO antenna is developed as a transmit antenna in reverberation chambers, and we believe that it will find more applications in other systems, such as micro base station antennas in wireless communication systems.
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| 2. |
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| 3. |
- Al-Rawi, Ali, 1985, et al.
(författare)
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The Double-sided 4-port Bow-tie Antenna: A New Compact Wideband MIMO Antenna
- 2013
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Ingår i: 7th European Conference on Antennas and Propagation, EuCAP 2013, Gothenburg, Sweden, 8-12 April 2013. - 2164-3342. - 9788890701832 ; , s. 3731-3735
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Konferensbidrag (refereegranskat)abstract
- We present a new compact ultra-wideband 4-port antenna for use in MIMO systems, such as in reverberation chambers for OTA measurements. The new antenna is based on the self-grounded bow-tie antenna with a very compact size. The design was done through an optimization by employing the genetic algorithm in order to obtain low reflection coefficient and mutual coupling between ports. The designed antenna has an embedded radiation efficiency higher than -0.35 dB, reflection coefficient below -7 dB, mutual coupling between ports below - 12.5 dB (in most frequencies below -20 dB), over a frequency range of 0.4–15 GHz.
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| 4. |
- Kildal, Per-Simon, 1951, et al.
(författare)
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Characterization of Reverberation Chambers for OTA Measurements of Wireless Devices: Physical Formulations of Channel Matrix and New Uncertainty Formula
- 2012
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Ingår i: IEEE Transactions on Antennas and Propagation. - 0018-926X .- 1558-2221. ; 60:8, s. 3875-3891
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Tidskriftsartikel (refereegranskat)abstract
- The paper deals with reverberation chambers for over-the-air (OTA) testing of wireless devices for use in multipath. We present a formulation of the S-parameters of a reverberation chamber in terms of the free space S-parameters of the antennas, and the channel matrix in the way this is known from propagation literature. Thereby the physical relations between the chamber and real-life multipath environments are more easily explained. Thereafter we use the formulation to determine the uncertainty by which efficiency-related quantities can be measured in reverberation chamber. The final expression shows that the uncertainty is predominantly determined by the Rician K-factor in the reverberation chamber rather than by the number of excited modes, assumed by previous literature. We introduce an average Rician K-factor that is conveniently expressed in terms of the direct coupling between the transmitting and receiving antennas (corresponding to a line-of-sight contribution) and Hill's transmission formula (corresponding to a multipath or non-line-of-sight contribution). The uncertainty is expressed in terms of this average K-factor and geometrical mode stirring parameters, showing strong reduction by platform and polarization stirring. Finally the formulations are verified by measurements, and the new understanding of uncertainty is used to upgrade an existing reverberation chamber to better uncertainty.
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| 5. |
- Orlenius, Charlie, 1976, et al.
(författare)
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Analysis of MIMO OTA measurements for LTE terminals performed in reverberation chamber
- 2012
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Ingår i: European Conference on Antennas and Propagation, EuCAP 2012, Prague, Czech Republic, 26-30 March 2012.
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Konferensbidrag (refereegranskat)abstract
- The evolution of measurement systems that can capture the performance of multi-antenna systems is an important and highly prioritized point of discussion for the antenna community. This paper gives a state-of-the-art recollection of the latest findings in MIMO OTA measurements utilizing reverberation chambers, specifically relating to LTE terminals.
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| 6. |
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| 7. |
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| 8. |
- Lötbäck Patané, Christian, 1985, et al.
(författare)
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Analysis and improvement of reverberation chamber method for characterization of small and terminal antennas
- 2011
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Ingår i: European Conference on Antennas and Propagation 2011, 11-15 April 2011, Rome. - 9781457702501 ; , s. 1832 - 1836
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Konferensbidrag (refereegranskat)abstract
- In this paper the uncertainty of reverberation chamber measurements is determined by a procedure proposed for a possible CTIA standard. The different contributions to the measurement uncertainty are analyzed. By improving the mode stirring based on this knowledge, it was possible to reduce the standard deviation of the measurements from about 0.5 dB to 0.3 dB for frequencies above 600 MHz.
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| 9. |
- Aijaz, N., et al.
(författare)
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Active throughput measurements for complete MIMO WLAN systems using dual reverberation chamber technique
- 2010
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Ingår i: 2010 International Workshop on Antenna Technology (iWAT 2010), 1-3 March 2010, Lisbon, Portugal. - 9781424448838
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Konferensbidrag (refereegranskat)abstract
- A reliable, repeatable and fast measurement procedure for a complete Multiple-Input-Multiple-Output (MIMO) Wireless Local Area Network (WLAN) system is presented. Application level throughput is presented as a performance metric to reflect the actual throughput delivered to the end user by a WLAN system. The employed technique involves the use of two reverberation chambers to cope with the real world scenario of low Signal to Noise Ratio (SNR) proximity and to effectively control the rank of a communication channel.
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| 10. |
- Orlenius, Charlie, 1976, et al.
(författare)
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Active MIMO performance measurements in connected reverberation chambers
- 2010
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Ingår i: EuCAP 2010 Fourth European Conference on Antennas and Propagation, Barcelona, 12-16 April 2010.
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Konferensbidrag (refereegranskat)abstract
- In this paper a fast and repeatable way of characterizing active, MIMO-enabled wireless communication units is presented. The measurement setup utilizes two connected reverberation chambers, which introduces the possibility of controlling the wireless channel in detail. Throughput is used as performance metric, and will in this case include the effect of the antenna array on the total performance.
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