Objective: Perform channel measurements at W-bands by means of a beacon designed, developed and launched on a Cubesat platform.
Targeted Improvements: Augment ITU-R models for W-band with specific measurements such as:
i) Tropospheric scintillation at W-band including spectral properties & dependence on elevation angles,
ii) combination of cloud and attenuation effects,
iii) frequency scaling of rain attenuation,
iv) depolarization due to ice (fast XPD without concurrent attenuation).
Description: For large broadband satellite networks, the number of gateways may be such that the cost of the ground segment exceeds the cost of the satellite, even when using Q/V band in the gateway feeder link. The use of W-band as a feeder link frequency band in future HTS system could significantly reduce the cost of the ground segment. The usage of the spectrum available in W-band (70/80 GHz) for satellite communications will significantly reduce the number of gateways and consequently the overall cost of the ground segment. However, the channel models available from ITU are known to be accurate only until 30~40 GHz. Therefore new measurement campaigns are needed to characterize the channel propagation at W-band. In this activity a Cubesat shall be used to embark a beacon in W-band in order to perform channel measurement experimentation. The LEO orbit of the Cubesat, although different from the geostationary orbit of future operational satellites exploiting W-band, will allow to characterize fairly well all the major satellite channel impairments. In addition, supporting tools will be used to cope with the short contact times available for the measurements. In particular, an atmospheric channel simulator will be used to bridge the gap between the relatively short LEO measurements and the statistical reliability needed for GEO propagation measurements. The collected Cubesat channel measurements will be used to tune the atmospheric channel simulator. Satellite movement effects will be de-convolved from measurements in order to extrapolate the equivalent GEO propagation channel. The activity shall design and develop the W-band beacon together with the propagation terminal and the Cubesat platform that will host the beacon. Second, the beacon will be tested, integrated in the platform launched using the first flying opportunity. A measurement campaign of at least two years duration shall follow.