Broadband RCS reduction by gradient index meta-surface composed of Jerusalem-shaped patches

A gradient index meta-surface composed of Jerusalem-shaped unit cells is proposed to provide a discontinuous reflected phase gradient distribution for manipulating incident wave in broadband. The Jerusalem-shaped unit cells are located on a high dielectric constant substrate with a perfect conducting ground, and their sizes are adjusted to achieve a desired gradient phase distribution. The proposed meta-surface can focus the reflected wave to fixed angles, which exhibits potential application in backward scattering reduction. Both the simulation and measurement results show that the backward radar cross section (RCS) of the proposed meta-surface can be reduced as large as 10 dB within the range from 16.5 GHz to 22.5 GHz, comparing with that of the metal plate with the same size.