Cloud Attenuation in the Q band: Estimation from Experimental Data of Excess Attenuation

Although rain is the main atmospheric impairment to millimeter waves, the adverse impact of clouds becomes more relevant. This contribution presents a study carried out at the Universidad Politécnica de Madrid, in which cloud attenuation has been estimated from 5-year of experimental data of excess attenuation, gathered with a Q-band beacon receiver, using a novel method to separate the contribution of clouds in the absence of rain in site and along the path. In this method, different ancillary data obtained from co-located instruments- a disdrometer and a Ka-band beacon receiver- are used to detect in-site rain, whereas possible rain events along the path are detected from fade slope information, since fade slope is expected to be higher with rain than with cloud attenuation. Results are compared with available cloud attenuation models including the recently published Rec. ITU-R P.840-9.