Enhancing Backward Scattering Using Metasurfaces

In this letter, we propose the design of metasurfaces for enhancing backscattering under oblique incidence. Through reflective phase profile design along the surface, an equivalent wave-vector can be generated, with double magnitude but opposite direction to the parallel component k|| of the wave-vector k0 of incident waves. A modified metallic square loop structure is used to achieve the required phase profile under oblique incidence. Through the phase gradient design, the metasurface can reflect incident waves backwards at 9.8GHz and the optimized frequency band can reach to 2.5GHz under transverse electric (TE) polarizations. Two prototypes were fabricated and measured. Both the simulation and experiment results verify the good backscattering enhancement performance of he metasurface.