Characterization of GSAT-14 Satellite Ka-Band Microwave Signal Attenuation Due to Precipitation Over a Tropical Coastal Station in the Southern Peninsular Region of the Indian Subcontinent

This paper focuses on study of attenuation of microwave propagation at Ka-band frequencies due to precipitation over an Indian Tropical station, Thiruvananthapuram (8.5 degrees N, 76.8 degrees E). The station is located on the gateway of S-W Indian monsoon into the subcontinent characterized with prolonged rain for a period of about 9 months. A satellite link has been established at Thumba, Thiruvananthapuram, between Ka-band receiver operating at 20.2 and 30.5 GHz and GSAT-14 as part of Indian Space Research Organization's Ka-band propagation experiment. The concurrent measurements of Ka-band signals and the precipitation, using a collocated laser precipitation monitor instrument, were carried out during the entire period of Indian monsoon. The study focuses on quantifying the dependence of Ka-band attenuation on rain rate during the rain-dominated premonsoon and summer monsoon seasons. The observed attenuation has been evaluated with ITU model.