Cross-polarization discrimination measurements on satellite-to-ground path using CS-3 beacon signal

Characteristics of cross-polarization discrimination (XPD) are investigated by the CS-3 beacon signal observations on a Ka-band satellite-to-ground path for the years of 1988-1992. It is found that severe depolarization is not so much correlated with rainfall rates as the attenuation that is primarily concentrated in the summer season, and the additional XPD degradation due to the ice effects is rather enhanced as the height is decreased in the cold seasons. Such depolarization is considered to be caused by a differential phase shift (DPS) between the major and minor axes of the ice crystals, which are aligned in nearly horizontal and vertical directions, respectively, in view of the distribution of the cross-polarized phases. The improvements of the observed XPD by the DPS cancellation is estimated to be larger than 10 dB at rainfall rates smaller than 10 mm/h which will not exceed a general rain margin