Figure 1

Concept of a broadband polarization-insensitive cloak based on mode conversion and a fabricated sample.

(a) The schematic plot of the one-dimensional cloaking device. Inside a one-dimensional waveguide bounded by PEC walls, the regions with gradual color represent GIMs with same thickness d. The filled media is air. Particularly, the middle part between two dashed black lines is the designed device showing cloaking effect. The red arrows indicate the propagating process of EM wave inside. When a waveguide mode (propagating wave, PW) is incident from left to the cloaking device, the PW is gradually converted into two SWs propagating along the interfaces between GIMs and air. After the SWs pass the middle point where the index is maximal, they will be gradually converted back into PW, leaving the device. The shadow region shows the cloak region. (b) The experimental setup at microwave. The samples of GIMs are fabricated with four dielectrics (their permittivities are, respectively, 2.2, 3.5, 7.5 and 16), all at the height of 10 mm and at the width of 7.2 mm. The unit cell is 3.6 mm × 3.6 mm. The width of air in middle is 22.5 mm. The microwave emitter and receiver are installed to both sides of the waveguide, with both widths of 22.5 mm.