1. Department of Electrical and Electronic Engineering Technology, University of Johannesburg, Johannesburg, South Africa
2. Institute of Nano Engineering Research (INER), Department of Chemical, Metallurgy and Material Engineering, Tshwane University of Technology, Pretoria, South Africa
3. Department of Electrical Engineering, French South African Institute of Technology (F’SATI), Tshwane University of Technology, Pretoria, South Africa