1. Microelectronics Research Unit Faculty of Information Technology & Electrical Engineering University of Oulu-Finland P. O. Box 8000 FI-90014 Oulu Finland
2. Centre for Wireless Communications Faculty of Information Technology & Electrical Engineering University of Oulu-Finland P. O. Box 8000 FI-90014 Oulu Finland
3. Solaronix SA Rue de l’ Ouriette 129 CH-1170 Aubonne Switzerland