1. Univ Rennes, CNRS: Institut d'Électronique et de Telecommunications de Rennes (IETR), UMR 6164,Rennes,France,35000
2. University of Siena,Department of Information Engineering and Mathematics,Siena,Italy,53100
3. European Space Agency - ESA/ESTEC: Radio Frequency Payloads & Technology Division,Noordwijk,The Netherlands