Design and engineering of metasurfaces for high-directivity antenna and sensing applications Badreddine Ratni, Elena Bochkova, Gérard-Pascal Piau, André de Lustrac, Anatole Lupu and Shah Nawaz Burokur EPJ Applied Metamaterials, 3 (2016) 4 Published online: 26 July 2016 DOI: 10.1051/epjam/2016008