1. Functional Devices Laboratory, Institute of Advanced Technology, Universiti Putra Malaysia (UPM), 43400 Serdang, Selangor, Malaysia
2. Department of Electrical and Electronic Engineering, Universiti Putra Malaysia (UPM), 43400 Serdang, Selangor, Malaysia
3. Wireless and Photonic Network Research Center, Department of Computer and Communication Systems Engineering, Universiti Putra Malaysia (UPM), 43400 Serdang, Selangor, Malaysia