1. Engineering Product Development, Singapore University of Technology and Design, 8 Somapah Road, Singapore 487 372
2. DIEF − Università di Modena e Reggio Emilia, Via P. Vivarelli 10/1, Modena 41125, Italy
3. Electronics Department, National Institute of Astrophysics, Optics and Electronics, Puebla 72840, Mexico
4. Institute of Materials Research and Engineering, Agency for Science Technology and Research, 2 Fusionopolis Way, Singapore 138 634