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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Contribution au dimensionnement d'une liaison radio sur le corps humain :études canal et antenne à 60 GHz

Razafimahatratra, Solofo 14 November 2017 (has links) (PDF)
The band around 60 GHz is interesting for BAN applications mainly for lowerinterference than at microwave frequencies, wide available band adapted to On-Off Keying(OOK) modulation for low energy consumption and low data rate communication (under10 Mbps), antenna miniaturization. Nevertheless, due to high attenuation at this frequency,the design of a reliable and energy-effective communications for BANs requires a detailedanalysis of the body channel. A planar and compact SIW horn antenna was designed and usedfor body channel measurements at 60 GHz. The main contribution in the antenna design is thebandwidth enhancement covering the whole available band around 60 GHz compared to thesame antenna type available at this frequency. The on-body measurements with this antennashow that short-distance and LOS (Line Of Sight) links are possible at 60 GHz. The bodydynamic is taken into account by statistical off-body channel measurements. For the firsttime, measurements are done for the same scenarios at 60 GHz and another frequency in theUltra WideBand suitable with OOK impulse radio modulation. By taking into accounttransmission power standards and low power consumption receivers sensitivity in theliterature, the potentiality of 60 GHz for BAN is shown with an outage probability lower than8 % whereas this parameter is lower than 15 % at 4 GHz. When characterizing antenna onbody, difficulties arise for antenna de-embedding due to the antenna-body coupling. In fact,the antenna gain depends on transmitter-receiver distance on body. For the first time, aformulation of the vertical dipole gain on body is given. Also a new theoretical approachbased on the complex images method is proposed to compare two types of canonical antennaradiating on body. A vertical dipole and different rectangular apertures are normalizedthrough their input impedance with the same accepted power. The aperture input impedanceformulation has been developed during this study. The aperture efficiencies are 10% higherwhen antennas are at a height lower than 3 mm above the body phantom. The received powerincreases with the antenna size only for phantom direct touch, the difference among antennasis lower than 4 dB for the considered antennas limited with a monomode configuration. / Doctorat en Sciences de l'ingénieur et technologie / info:eu-repo/semantics/nonPublished

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