1. Radio Communication Engineering Department (RaCED), Faculty of Electrical Engineering, Universiti Teknologi Malaysia, 81310 Johor, Malaysia
2. Mechanical Engineering Department, Faculty of Engineering, Sudan University of Science and Technology, Khartoum 407-111, Sudan
3. Electronic and Electrical Engineering Department, School of Engineering and Built Environment, Edinburgh Napier University, Merchiston Campus, EH10 5DT Edinburgh, UK