Rain drop size distributions (DSD) are measured with disdrometers at five different climatic locations in the Indian tropical region. The distribution of drop size is assumed to be lognormal to model the rain attenuation in the frequency range of 10-100 GHz. The rain attenuation is estimated assuming single scattering of spherical rain drops. Different attenuation characteristics are observed for different regions due to the dependency of DSD on climatic conditions. A comparison shows that significant differences between ITU-R model and DSD derived values occur at high frequency and at high rain rates for different regions. At frequencies below 30 GHz, the ITU-R model matches well with the DSD generated values up to 30 mm/h rain rate but differ above that. The results will be helpful in understanding the pattern of rain attenuation variation and designing the systems at EHF bands in the tropical region.
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