The objective of the mini-project (this activity goes hand in hand with the ''W-band technology developments towards first beacon-based propagation campaign'' activity) is to develop the technological building block needed to start characterising the W-band propagation channel.

The use of higher frequencies is becoming necessary for supporting feeder links of High Throughput Telecom Satellites due to the larger bandwidths available. Q and V bands are now being considered as a baseline for next generation systems. The next step will be to look at W band. In order to understand the system sizing, it is necessary to have a good modelling of the propagation channel. So far no measurement campaign has been done, therefore it is needed to start characterizing the channel. This study aims to develop the technological building block needed to start characterising the W-band propagation channel.Two activities are foreseen within this study:1) W-band propagation channel characterisation through ground-based radiometric measurements This activity shall cover the whole cycle of the measurement campaign including the radiometer modification, campaign execution and data processing. Concerning the W-band radiometers and more particularly the development of a sun-tracking system for the ATPROP 15/90 GHz radiometer; this development should be feasible in 6 months maximum, and will allow using the radiometer currently available in ESTEC for W-band radiometric measurements using the sun as an active source. Once the first development is completed, a W-band sun-tracking radiometer measurement campaign shall be started for collecting the measurements. These observations will allow evaluating also the rain attenuation, which would not be possible if using only a radiometer measuring the sky brightness. Finally the W-band radiometric characterisation will be concluded with the data processing for deriving statistical propagation models of the W-band satellite channel; an additional complexity is represented by the non-stationary nature of the problem, therefore proper models shall be derived for extrapolating statistics as a function of the elevation angle.These 3 steps will provide on one hand validation figures for the link budget of the following W Band Spaceborne mission and on the other hand reference data for the future campaign using a W Band payload. Timeframe: T0 - T0 + 24m 2) Design of the propagation terminal and identification of technological developments. Timeframe: T0+6m - T0+18m