Assessment of performance of a Ka-band broadcasting reconfigurable satellite antenna with adaptive mitigation for atmospheric attenuation

The flexibility given by a reconfigurable antenna can be exploited in various ways: redirecting capacity, tailoring the shape so as to match the borders of the served region, maximizing the total throughput etc. Another possibility, particularly valuable above the Ka-band owing to the sensitivity to atmospheric attenuation, is that of minimizing the number of non served users in a broadcasting system. This is achieved by redirecting the power flux so as to concentrate more power towards regions affected by rain. The efficient utilization of the limited power available on board allows the achievement of the same system availability of a fixed antenna but with lower power levels. Modern satellite-antenna technology could reach a spatial resolution on ground which is comparable to that of the atmospheric weather features to be mitigated. In the case of Europe this goal could be obtained by reflector antennas of about 2 m diameter illuminated by a focal array composed by about 100 feeds. The paper presents a first step towards an extensive assessment of the performance of such a system operating in the ka band based on simulations utilizing high resolution weather spatial fields provided by the European Centre for Medium-range Weather Forecast (ECMWF) and concurrent Meteosat images. The simulation will cover a significant period of time (some years) so as to provide a statistically sound estimate of the adaptive gain. A balance of the adaptive gain vs the limitations of reconfigurable beam-forming network will be attempted so as to assess the cost- and risk-effectiveness of such technique for systems in the near future.