Estimation of cross-polarization due to rain over some stations in Nigeria

Abstract

The statistical morphology of cross-polarization due to rain is of considerable interest to system designers in order to estimate accurately the signal total availability of time. In this paper, an attempt has been made to compute cross-polarization of millimeters waves in the Ku- and Ka-band frequencies range due to rain. ITU-R P.618-9 model has been used to predict cross-polarization discrimination (XPD) over three different elevation angles in Nigeria with modification using log-normal distributions of raindrop sizes at 20°C and assuming circular polarization for Earth–satellite propagation paths. The study includes a number of earth stations in Nigeria, namely Akure, Ikeja, Calabar, Minna, and Kano. Variations of co-polar attenuation with XPD as well as cumulative distribution of XPD have also been presented. The result of the estimation of XPD at various elevations angles and at the frequencies considered shows the dependence of XPD on frequency, co-polar attenuation, and rainfall rates. The orthogonal channels at the same frequency situated at the coastal region is prone to higher amount of unwanted signal mostly at the elevation angle of 23° (for communication links over the Indian Ocean) than at other elevation angles considered in this report.