Q-Band LEO Earth Observation Data Downlink: Radiowave Propagation and System Performance

Earth Exploration Satellite Service (EESS) systems gather data about the Earth and its natural phenomena. Frequency bands traditionally employed by high-rate telemetry to download data from the satellite to the ground station, such as the X band (8 GHz), have become crowded. Higher frequency bands allow increasing the downlink throughput, as required by current advanced, multi-frequency sensors onboard the spacecraft (S/C). Some systems are already using or planning to use K-band (26 GHz) frequencies. The next band under consideration that can offer an increase in data volume return is the Q band (40 GHz). This paper studies the radiowave propagation aspects and the end-to-end system performance of Q-band Earth observation (EO) data downlink systems. Using standard ITU-R propagation prediction models and state-of-the-art technology specifications, simulation results are given in terms of obtained data return. Different orbit altitudes, satellite platform classes, ground station locations, antenna diameters and transmission types are considered.