Moderate rain rate characterisation for small fade margin systems

The use of K/Ka band frequencies (20/30 GHz) and above for Earth-space communications is considered. As hardware prices are becoming affordable and large bandwidths can be offered, the success of systems operating at these frequencies will certainly be dependent on the services and quality of service (in a wide sense) offered. The tropospheric propagation channel induces dispersion, multipath, noise and fading. The characterisation of these impairments is important for estimating availability, design, and predicting effectiveness of a few possible countermeasures that can be implemented. The attenuation induced by gases (always present), clouds and rain must be considered on the slant path. We hereby consider mainly aspects related to moderate rain events that are important for low fade margin systems.