Calculation of Rain Attenuation For Higher Frequencies

Under The Guidance ofDr. K. Sarat Kumar

Professor

kailash202012@gmail.comStudent(M.Tech) -K L University

Presenter: Kailash Karki 152040006

Introduction

• Attenuation implies decrease in signal amplitude.

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Statement of Problem

Why higher frequency band??

Why we need to study rain attenuation ??

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Assumptions

o Shape of raindrops is spherical.

o As the wave propagates through the volume of rain ,its intensity decays.

o Each drops contributions are independent of the other drops and each contibution is additive.

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Terminology Used:

• Specific Attenuation

• Exceedance Probability

• Slant Path Length

• Horizontal Reduction Factor

• Vertical Adjustment Factor

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Prediction of Rain Attenuation

ITU-R Model

Rain Attenuation(db) = Specific attenuation * Effective path length

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Specific Attenuation is obtained from the rain rate(mm/h) using the power law relationship A(dB/km) = K* Rα

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Effective Path Length

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Calculate Slant Path Length

Horizontal Projection

Horizontal Reduction Factor

Vertical Adjustment Factor

Effective Path Length = Horizontal Projection * Vertical Adjustment Factor

Used Parameters

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Parameters Value

Rain Rate 58.43 mm/hr

Elevation Angle 43 (degree)

Latitude of Earth Station 17.20 (degree)

Rain Height 4.698 Km

Simulation Results

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Fig: Regression Coefficient, K Vs Frequency

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Fig: Regression Coefficient, K Vs Frequency

Contn..

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Fig: Specific Attenuation Vs Frequency

Contn..

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Fig: Effective Path Length Vs Frequency

Contn..

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Fig: Total Attenuation Vs Frequency

Contn..

15Fig: Attenuation For Different Exceedance Probability

Conclusion

• At high frequency the effect of rain is severe.

• For twenty four hours signal availability effective rain fade mitigation techniques should be implemented.

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