Wideband Radar-Cross-Section Reduction Using Parabolic Phased Metasurfaces

This letter presents a fast and efficient metasurface design approach without using time-consuming optimization algorithms, for wide-angle low scattering applications and wideband radar-cross-section (RCS) reduction. Using ray-tracing theory and by engineering the proposed metasurfaces to exhibit a diffusive parabolic phase distribution across its aperture at frequencies other than the center frequency (f = 18 GHz), significantly diffused backscattering is guaranteed by redirecting the reflected energies over all directions over a wide range of frequencies. Based on the proposed approach, the scattering behavior of metasurfaces with parabolic phase distributions from 1f to 20f was carefully investigated. Numerical and experimental results both demonstrated that a metasurface of phase profile at 5f is extremely powerful in distributing the scattering energy more uniformly than a metasurface of 1f phase profile. The designed metasurfaces using the proposed approach achieved more than 10 dB monostatic/bistatic RCS reduction over a wideband frequency range from 12 to 24 GHz (66.7%) and even for off-normal incidence up to 60 & DEG;. The proposed approach can overcome the inherent challenges of ensuring wide scattering angle over wideband frequencies of conventional chessboard and coding metasurfaces in the literature.