Ultrathin RCS Reduction Metasurface Based on Integer and Fractional Vortex Waves

In this paper, an ultrathin radar cross section (RCS) reduction metasurface is designed and realized by reflection-type vortex waves with various topological charges. Due to the singularity of the OAM characteristics, a significant RCS reduction is obtained at the operating frequency of 14GHz. Based on the fact that fractional-order vortex waves have unique radial amplitude zeros in addition to amplitude zero in the center, the monostatic RCS reduction characterization of fractional-order vortex metasurface is also mainly discussed. By analyzing the orbital angular momentum spectrum of different fractional vortex waves and field variation, the singularity range can be effectively manipulated so that the singularity is transmitted in the radial direction. The simulated results demonstrate that different OAM modes can be generated, and the monostatic RCS reduction over 30dB can be obtained at 14GHz under the normal incidence of the plane wave. Moreover, the thickness of the proposed RCS reduction metasurface is about 0.05 wavelength of the operation resonant frequency, which indicates that the metasurfaces have the characteristic of ultrathin. The far-field features of these metasurfaces show that they have prospective application value in scattering control technology.