1. School of Electrical and Electronic EngineeringNanyang Technological University 50 Nanyang Avenue Singapore 639798 Singapore
2. CINTRA UMI CNRS/NTU/THALES 3288Research Techno Plaza 50 Nanyang Drive, Border X Block, Level 6 Singapore 637553 Singapore
3. Institute of ElectronicsMicroelectronics and Nanotechnologies (IEMN)CNRS UMR 8520University of Lille 59650 Villeneuve d'Ascq Cedex France