1. Department of Physics Laboratory of Energy Electrical and Electronics Systems University of Yaoundé I Yaoundé Cameroon
2. Multidisciplinary Laboratory (MLAB), International Centre for Theoretical Physics (ICTP) Trieste Italy
3. Department of Physics Laboratory of Electronics and Automatics University of Douala Douala Cameroon
4. Electrical and Electronics Engineering Xiamen University Malaysia Sepang Selangor Malaysia
5. Electrical, Electronic and Systems Engineering Universiti Kebangsaan Malaysia Bangi Selangor Malaysia