3D Conformal Metasurfaces for RCS reduction of 3D Targets at Microwave Frequencies

It is noted that most of the reported metasurfaces in the literature were mostly designed to have a flat geometry, and their radar cross section (RCS) reduction performances in the non-planar scenarios was rarely investigated. In this paper, the RCS reduction performances of a metasurface when attached to a conformal (3D) metallic object is investigated. Four 3D objects are considered in this paper include cylindrical, spherical, sphere-cylinder, and the well-known NASA-almond. When the proposed metasurface is attached to a 3D object, it can achieve more diffused scattering patterns and wide scattering angles for both monostatic and bistatic RCS regardless of polarization of the incident waves and for a wide range incident angles. It is found that the proposed metasurface when attached to a 3D metallic object under normal and oblique incidence up to 60°, it can achieve more than 10 dB monostatic/bistatic RCS reduction from 12 to 24 GHz and even for off-normal incidence up to 60°.