Design and experimental verification of a two-dimensional phase gradient metasurface used for radar cross section reduction

Dealing with potential applications of phase gradient metasurfaces in stealth technologies, we propose to realize wide-band radar cross section (RCS) reduction by combining the two mechanisms of surface wave generation and anomalous reflection. A two-dimensional phase gradient based metasurface is designed using split-ring resonators. Around the designed central frequency f=10 GHz, the incident waves are coupled into surface waves propagating along the metasurface. While at the frequency band f>11 GHz, anomalous reflection and diffuse reflection occur. In this way, wide-band RCS reduction can be realized. A test sample with a total thickness of 2 mm is fabricated and its reflection and backward RCS are measured and compared with those of bare metallic plate with the same size. The comparison shows that the metasurface achieves more than 10 dB reduction in the measured wide range (9.5-17.0 GHz). The metasurface is a polarization independent, electrically thin, light-weight and wide-band, so it is of great application values in novel stealth technologies and materials.