(a) Principle diagram of the proposed unidirectional cloak, (b) the normal transmissions of the designed unidirectional cloak with and without the metal block, the simulated distributions of the E_x field and the amplitudes of the electric fields |E| at 16 GHz on the x-o-z plane, (c, d) for cloak without triangle metallic blocks, (e, f) for cloak with triangle metallic blocks. From reference [79]. Reprinted with permission from IOP.