The specific differential phase (Kdp) is a polarimetric radar observable which can be advantageous for rain rate estimation as it is not affected by absolute calibration errors and resistive to hail contamination. Its estimation, starting from the differential phase (?dp) consists of many processing steps and considerations which are more pronounced for the X-band due to the presence of non-negligible differential scattering phase (?co) and attenuation. In the thesis, the estimation of differential phase (?dp) and specific differential phase (Kdp) with the X-band Doppler polarimetric radar IDRA located in Cabauw, the Netherlands, is presented along with an approach to assess the estimated results based on the self-consistency of the radar observables. The effect of attenuation and a potential correction algorithm are also discussed.