Sparse Metasurfaces for Scattering Cross Section Reduction of Arbitrarily Shaped Metallic Bodies

Reducing the scattering cross section (SCS) of metallic objects plays a key role in stealth technology. In this work, sparse metasurfaces are designed through numerical calculations of Green's functions and are proposed to reduce the electromagnetic scattering of metallic cylinders. The metasurfaces are composed of relatively sparse meta-atoms, limited only by the impedance density without considering any resonance factor. The diameter of the metallic cylinders is of the order of one wavelength around the operating frequency of 5 GHz. By optimizing the load impedance distribution of the sparse metasurfaces coating the cylinders, the SCS of the cylinders can be considerably reduced. To experimentally demonstrate the concept, several prototypes are fabricated and tested in a microwave anechoic chamber. The experimental measurements are in good agreement with the numerical simulations and verify the consistent performance of the metasurfaces in SCS reduction.