| 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. |
- Asghar, A. M., et al.
(författare)
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A multiwideband planar monopole antenna for 4G devices
- 2013
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Ingår i: Microwave and Optical Technology Letters. - : Wiley. - 1098-2760 .- 0895-2477. ; 55:3, s. 589-593
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Tidskriftsartikel (refereegranskat)abstract
- This article presents a compact multiband planar antenna designed for mobile phone applications.The antenna performance is achieved by designing a planar monopole antenna into distributed radiating elements. The proposed antenna is comprised of a chopped circular radiator appended with a meander line and an L-strip coupled element, which is an extension of the ground plane. The combination of a chopped circular patch and L-shaped coupling strip residing on the top side generates lower band while upper band resonances are attained separately by chopped circular resonator and meander line elements. The antenna shows a planar structure which occupies an area of 56 x 17.6 mm and can be directly printed onto a circuit board at low cost making it especially suitable for mobile phone applications. The manufactured antenna is experimentally verified and covers several wireless communication bands, such as LTE 750, GSM 850, GSM 900, DCS, UMTS-2110, Bluetooth, WLAN, WiMAX, and UWB. The high frequency structure simulation is used to design and analyze the antenna performance, and a practical structure was fabricated and tested. The measured and simulated return loss show good agreement.
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| 4. |
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| 5. |
- Carlberg, Ulf, 1978, et al.
(författare)
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Ray based multipath simulation tool for studying convergence and estimating ergodic capacity and diversity gain for antennas with given far-field functions
- 2010
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Ingår i: 20th International Conference on Applied Electromagnetics and Communications, Dubrovnik, Croatia, September 2010. - 9789536037582
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Konferensbidrag (refereegranskat)abstract
- We propose that the rich isotropic multipath environment should be a reference environment for OTA (over-the-air) characterization of wireless stations for use in multipath, in the same way as the anechoic environment is a reference environment for antennas mounted on masts and rooftops. The rich isotropic multipath environment is emulated by a well designed reverberation chamber, but also by a spherical array of probes in an anechoic chamber. The present paper describes a ray-based simulation tool, ViRM-Lab, which enables users to study the performance of arbitrary user-defined multiport antenna located in user-specified multipath environment. The antennas are defined by their far-field functions of the embedded element (with the other ports matched-load terminated). The environment can be determined by its Angle-of-Arrival (AoA) distribution, richness, and polarization balance. The code is made in such a way that the convergence of the cumulative distribution function (CDF) received on all ports can be studied, as well as the convergence of the statistical expectations when estimating the ergodic Shannon capacity and diversity gain.
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| 6. |
- Carlsson, Jan, 1962, et al.
(författare)
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About measurements in reverberation chamber and isotropic reference environment
- 2010
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Ingår i: 20th International Conference on Applied Electromagnetics and Communications, Dubrovnik, Croatia, September 2010. - : ICECom 2010. - 9789536037582
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Konferensbidrag (refereegranskat)abstract
- The paper discusses the need for a reference environment for the characterization of small antennas intended to be used in multipath. The conclusion is that a good choice is the rich isotropic multipath environment as emulated by a well designed reverberation chamber, or possibly by a spherical array of antennas in an anechoic chamber. This is the only environment that enables a unique, objective and repeatable antenna characterization. This cannot be achieved in other environments. A few examples are given showing that the performances of different incremental antennas are very different and depend strongly on their orientations when they are located in a 2D horizontal multipath environment, with incident waves only in the horizontal plane, whereas their performances are equal and invariant to orientation when they are located in the rich isotropic multipath environment.
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| 7. |
- Einarsson, Bjarni Thor, 1987, et al.
(författare)
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Measurements of relative Throughput in Reverberation Chamber using Universal Software Radio Peripheral
- 2014
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Ingår i: 8th European Conference on Antennas and Propagation, EuCAP 2014, The Hague, The Netherlands 6-11 April 2014. - 2164-3342. - 9788890701849 ; , s. 1105-1108
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Konferensbidrag (refereegranskat)abstract
- This paper aims to show how Universal Software Radio Peripheral can be used in conjunction with reverberation chamber to measure throughput of wireless communication systems in Rich Isotropic Multipath environment. The results are in agreement with theories based on the threshold receiver model.
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| 8. |
- Hussain, Ahmed, 1985, et al.
(författare)
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A maternal diet of fatty fish reduces body fat of offspring compared with a maternal diet of beef and a post-weaning diet of fish improves insulin sensitivity and lipid profile in adult C57BL/6 male mice.
- 2013
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Ingår i: Acta Physiologica. - : Wiley. - 1748-1708 .- 1748-1716. ; 209:3, s. 220-234
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Tidskriftsartikel (refereegranskat)abstract
- Aim The maternal diet during pregnancy and lactation may affect the long-term health of the offspring. Our aim was to study how a fish or meat diet perinatal and after weaning affects body composition, insulin sensitivity and the profile of n-3 and n-6 polyunsaturated fatty acids (PUFAs) in breast milk, fat depots, skeletal muscle and liver in male adult mice offspring. Methods During gestation and lactation, C57BL/6 dams were fed a herring- or beef-based diet. Half of the pups in each group changed diets after weaning. In offspring, body composition measured by DEXA, plasma lipid profile and insulin sensitivity measured by euglycemic clamp or QUICKI were monitored to adulthood. Analysis of total FAs by GC-MS were performed in the diet, breast milk and in different tissues. Results At 9 week of age, offspring of herring-fed dams had less body fat than offspring of beef-fed dams. Mice fed herring after weaning had increased insulin sensitivity at 15 week of age, reduced total plasma cholesterol and triglyceride levels, and compared with beef-fed mice, larger interscapular brown adipose tissue depots. The FA composition of the maternal diet was mirrored in breast milk, and the herring diet significantly affected the FA profile of different tissues, leading to an increased content of n-3 PUFAs. Conclusion A herring-based maternal diet reduces body fat in the offspring, but the insulin sensitivity, plasma lipids and amount of brown adipose tissue are affected by the offspring's own diet; the herring diet is more beneficial than the beef diet.
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| 9. |
- Hussain, Ahmed, 1985, et al.
(författare)
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About Random LOS in Rician Fading Channels for MIMO OTA Tests
- 2011
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Ingår i: ISAP2011, Jeju, Korea, 15-18 October 2011.
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Konferensbidrag (refereegranskat)abstract
- It is often claimed that Rician fading must also be included for Over-The-Air (OTA) testing of mobile devices with Multiple-input Multiple-output (MIMO) capabilities. However, the Line-Of-Sight (LOS) component varies with orientation and location of the mobile device. Therefore, we study Rician channels with random LOS to determine its significance
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| 10. |
- Hussain, Ahmed, 1985, et al.
(författare)
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Analysis of statistical uncertainties involved in estimating ergodic MIMO capacity and diversity gain in Rayleigh fading environment
- 2010
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Ingår i: 20th International Conference on Applied Electromagnetics and Communications, Dubrovnik, Croatia, September 2010. - : ICECom 2010. - 9789536037582
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Konferensbidrag (refereegranskat)abstract
- Statistical uncertainties involved in the evaluation of ergodic MIMO capacity and diversity gain in a fading environment is investigated. The study is based on results from a numerical simulation tool called "Rayleigh-Lab. " This tool can be used for accuracy investigation of MIMO capacity and diversity gain, and to determine the number of independent samples needed to estimate them with a reasonable level of confidence. The MIMO capacity is evaluated using Shannon's channel capacity formula. Two different methods of evaluating diversity gains are compared: based on CDF curves, and based on estimating correlation and radiation efficiency and then using them in a newly available compact formula for calculating the diversity gain. Rayleigh-Lab emulates Rayleigh channels by generating sequences of random complex numbers and it provides a convenient graphical user-interface for a pedagogical study of average power level (proportional to antenna efficiency), correlation, diversity gain and maximum available capacity.
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