| 1. |
- Degauque, Pierre, et al.
(författare)
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Antennas and diversity : from narrowband to ultra-wide band.
- 2006
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Ingår i: Mobile Broadband Multimedia Networks. - : Academic Press. - 0123694221 ; , s. 218-276
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Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- This chapter provides new insights on antennas, including diversity schemes and UWB applications. It is important to remember that antenna performances are strongly dependent on the electromagnetic properties of the medium in its immediate vicinity. This is a critical point for handset antennas, for example, since the user's hand and body strongly affect the radiation efficiency. Taken together, the total radiated power in the transmission mode and the total radiated sensitivity in the receiving mode provide a general idea of the handset terminal's behaviour in its environment. However, as outlined in Section 5.2, in order to characterise antenna efficiency precisely, it is first necessary to introduce and define such figures of merit as the mean effective gain and the mean effective radiated power, taking the multipath structure of the communication channel into account. For this, measurement techniques must be reproducible. Two of these techniques have been studied in depth. In the first, which is based on the use of a reverberation chamber, multiple reflections on the walls reproduce ideal Rayleigh channels; in the second, the transmitting antenna is placed in an anechoic chamber, allowing the modification of the antenna radiation pattern, due to a phantom that simulates the user's body, to be clearly demonstrated. One of the main factors influencing the measurement results is, of course, the electrical properties of the phantom material. However, both the position of the phantom hand, or in other words, the way a handset is held, and the position of the antenna handset relative to the head are also quite critical. These issues of measurement repeatability and accuracy were widely discussed during the COST 273 Action, with a focus on updating the standardised measurement techniques.
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| 2. |
- Lau, Buon Kiong, et al.
(författare)
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Assessment and modelling of terminal antenna systems
- 2012
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Ingår i: Pervasive Mobile & Ambient Wireless Communications - The COST Action 2100. - London : Springer London. - 9781447123149 ; , s. 149-195
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Bokkapitel (refereegranskat)abstract
- The pervasive use and insatiable demand for high-performance wireless devices globally are driving the development of new communication technologies and standards. In this chapter, we present advancements in the area of terminal antenna systems and describe how they play a major role in enabling strict performance requirements to be met in future systems. As opposed to conventional systems that do not require explicit considerations of the terminal antenna beyond the satisfaction of some predefined design criteria in impedance bandwidth, radiation pattern and efficiency, multiple antenna systems in upcoming and future wireless networks must deliver significantly higher performance goals.
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| 3. |
- Lau, Buon Kiong, et al.
(författare)
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Multiple antenna terminals
- 2011
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Ingår i: MIMO: From Theory to Implementation. ; , s. 267-298
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Bokkapitel (övrigt vetenskapligt/konstnärligt)
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| 4. |
- Sibille, Alain, et al.
(författare)
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Future trends and recommendations
- 2016
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Ingår i: Cooperative Radio Communications for Green Smart Environments. - 9788793379145 - 9788793379152 ; , s. 469-486
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Bokkapitel (refereegranskat)
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| 5. |
- Sibille, Alain, et al.
(författare)
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Guest Editorial AWPL Special Cluster on Impact of User-Related Randomness on Antennas and Channels
- 2017
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Ingår i: IEEE Antennas and Wireless Propagation Letters. - 1548-5757 .- 1536-1225. ; 16, s. 1840-1842
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- The papers in this special issue focus on the impact of user-related randomness on antennas and channels. In the early days of telecommunications, most antennas were considered as fixed installations, and their performance was determined in terms of their directivity and radiations patterns when the polarizations of the antennas on the transmitting and receiving sides were aligned. With the birth of satellite communications, there soon became a need for reusing the frequencies by polarization multiplexing, resulting in dual polarized systems with an even stricter requirement to alignment in order to avoid interference between the two communication channels. Furthermore, mobile communications resulted in random channels owing to both fast Rayleigh fading and slow shadow fading. Nowadays, wireless devices and base stations/access points are used more and more in hugely differing contexts and environments for terminals. The papers in this issue have been prepared in this context, the aim being to help make better known the issues raised above from the antennas and propagation community and to contribute to foster research and development in this area.
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