Measuring and Modelling the Scattering Parameters of the Wet Radome of the Swiss Weather Radars

The radome of weather radars can be covered with a layer of water, degrading the quality of the radar products. Considering a simplified setup with a planar replica of the Swiss weather radars' radome, we measure and model analytically the scattering parameters of the multilayered radome sample, with and without water. The measured reflectance of the dry radome sample is consistent with the one modelled according to the manufacturer specifications. As regards the wet radome sample, for thick layers the distribution of the water complies with the model's hypothesis of a homogeneous film of uniform thickness. Qualitative agreement is also found for the meteorologically relevant thin layers, but because the water forms droplets, the results can be compared quantitatively only to a limited extent. Simulations with the General Reflector Antenna Software (GRASP) from TICRA complement the study for a more realistic setup with a spherical radome.