1. Federal University of Campina Grande (UFCG),Department of Electrical Engineering,Federal,Campina Grande,Brazil
2. Federal Institute of Paraiba (IFPB): Group of Telecommunications and Applied Electromagnetism (GTEMA-IFPB),João Pessoa,Brazil
3. Univeristy of Pisa,Dipartimento Ingegneria dell'Informazione,Pisa,Italy