Ka-band rain attenuation by radiometer method

This paper would focus on investigating signal attenuation of Ka-band at zone N by using radiometer method and finally analyses the collective data by new developing indirect equation is ratiometer equation. According to equation analysis, the signal attenuation of Ka-band frequency depends on the differentiation of noise signal between clear sky condition and rain condition. Consequently, increasing of noise signal level is the result from rain cloud absorbing and discharging. The experiment site in this article was located at King Mongkut´s Institute of Technology (KMITL) LadKrabang, Bangkok, Thailand (latitude 108E° and longitude 13.7N°) which represent for the tropical zone site. During 12 months of experiment period from May 2001 to April 2002, the results reveals clearly that the signal attenuation of Ka-band frequency are divided into 3 stages as follow: Stage I: signal attenuation before raining which is affect from rain cloud; Stage II: signal attenuation in raining period which is affect from rain; Stage III: signal attenuation after raining which is affect from high humidity. Finally, this paper will present worst month and lowest month in cumulative attenuation.