1. Department of Physics, Faculty of Sciences, University of Yaoundé 1, Yaoundé, Cameroon
2. Department of Electrical and Power Engineering, The University of Bamenda, Bamenda, Cameroon
3. Department of Electrical and Telecommunications Engineering, Ecole Nationale Supérieure Polytechnique, University of Yaoundé 1, Yaoundé, Cameroon
4. Centre de Recherche en Informatique, Signal et Automatique de Lille Laboratory, UMR, Centre National de la Recherche Scientifique, University of Lille, Villeneuve d’Ascq, France