Propagation Experiments in Madrid for the Ka and Q Bands: Recent Results and Rain Attenuation Modelling in the Earth-Satellite Channel

Most of the available rain attenuation models have been derived on the basis of experimental measurements carried out only at frequency bands below 20 GHz or with little data above this value. Universidad Politécnica de Madrid (UPM) is carrying out two experimental campaigns at the Ka and Q bands, measuring two beacon signals at 19.7 GHz (from the KA-SAT satellite) and 39.4 GHz (from the Alphasat satellite). Five years of measurements for each experiment are now available and have been processed. Attenuation results are presented in this paper and are used to assess the performance of fifteen rain attenuation models available in the literature. The best results are provided by the NTUA model, although some other ones, including the one recommended by the ITU-R, also yield relatively good predictions.