Prediction of rain-induced cross-polarization at microwave and millimeter wave bands in Guinea /
The effects of rain on microwave terrestrial communication systems paths have received considerable attentions especially at frequencies above 10 GHz. Rain induced impairment models have been formulated in recent decades with emphasis on signal attenuation. When using dual polarized communication sy...
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| Format: | Thesis |
| Language: | English |
| Published: |
Kuala Lumpur :
Kulliyyah of Engineering, International Islamic University Malaysia,
2015
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| Subjects: | |
| Online Access: | Click here to view 1st 24 pages of the thesis. Members can view fulltext at the specified PCs in the library. |
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| Summary: | The effects of rain on microwave terrestrial communication systems paths have received considerable attentions especially at frequencies above 10 GHz. Rain induced impairment models have been formulated in recent decades with emphasis on signal attenuation. When using dual polarized communication systems to increase channel capacity by a factor of two, not only differential attenuation occurs but also differential phase shift caused by deformed raindrops. However, these effects need to be investigated in tropical and sub-tropical regions such as Guinea. Employing this frequency reuse technique on either linear or circular polarization, some degree of interference, owing to a change of the transmitted energy from one polarization state to the other, is inevitable between the two polarizations. A measure of the degree of noise between the two orthogonal channels is the cross polarization discrimination (XPD). Therefore, in this work, a mathematical model has been developed to calculate the probability of exceedance for rain rates in the selected prefectures using 20 years data collected at the Guinean Meteorological Department. XPD becomes significant, numerically low, when the rain rate increases and for frequencies up to 30 GHz. XPD of 18.75 dB at 11 GHz and 17.49 dB at 19.3 GHz along a 1 km path link were recorded in Boke with 117 mm/h or 0.005 % probability of exceedance. For 116 mm/h or 0.011% exceedance level in Conakry, the 11 GHz and 19.3 GHz rain-induced cross polarization were 19.3 dB and 17.9 dB respectively. It can be concluded that the XPD is good in the northern and forest parts of Guinea with average rain rate less than 90 mm/h and fairly good in other part of Guinea. XPD is therefore acceptable for dual polarization systems. |
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| Physical Description: | xvii, 113 leaves : ill. ; 30cm. |
| Bibliography: | Includes bibliographical references (leaves 100-106). |