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

Abstract

In this paper an attempt has been made to compute cross-polarization of millimeter waves in the 30-35 GHz frequency range due to rain. Laws and Parson’s drop size distributions for oblate spheroid drops at 20ºC ITU-R (2002) model has been used to predict cross-polarization discrimination (XPD) for circular polarization. The study includes a number of earth stations in India, namely, Ahmedabad, Calcutta, Delhi, Gangtok and Jodhpur. Variations of co-polar attenuation with XPD have been shown. Cumulative time distribution of XPD has also been presented. The study reveals that cross-polarization depends on frequency, co-polar attenuation and rainfall rate. Comparison with measurement does not show good agreement although the two show the same trend. Extensive work on cross-polarization is required in the millimeter wave frequency range over a large number of earth stations in India using different drop size distributions and different polarizations.