Characteristics of Rain Attenuation for Microwave-to-terahertz Waveband from Raindrop Size Distribution Observation in Indonesia

Characteristics of rain attenuation for microwave-to-terahertz waveband have been investigated using raindrop size distribution (DSD) data collected by Parsivel (Particle Size Velocity) disdrometer network in Indonesia. The DSD data collected at Kototabang, Padang, Sicincin, Pontianak, Manado and Biak, were used to estimate specific rain attenuation by using T-Matrix method through Mie scattering assumption. The results of this study corroborate the regional variations of rain attenuation in Indonesia. Rain attenuation is smaller than the ITU-R model for lower frequency (< 10 GHz) and it is larger than the ITU-R model for higher frequencies (> 100 GHz). The largest difference between the rain attenuation obtained from measured DSD and ITU-R model is observed at Biak because the DSDs in this area contain more small-sized raindrop. This regional variation of rain attenuation should be considered in telecommunication system design especially at Q band and above.