RAIN ATTENUATION MODELING IN THE 10-100 GHz FREQUENCY USING DROP SIZE DISTRIBUTIONS FOR DIFFERENT CLIMATIC ZONES IN TROPICAL INDIA

Abstract

Rain drop size distributions (DSD) are measured with disdrometers at flve difierent 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{100GHz. The rain attenuation is estimated assuming single scattering of spherical rain drops. Difierent attenuation characteristics are observed for difierent regions due to the dependency of DSD on climatic conditions. A comparison shows that signiflcant difierences between ITU-R model and DSD derived values occur at high frequency and at high rain rates for difierent regions. At frequencies below 30GHz, the ITU-R model matches well with the DSD generated values up to 30mm/h rain rate but difier 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.