Wideband Radar-Cross-Section Reduction Using Parabolic Phased Metasurfaces

Abstract

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 ( <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">f =</i> 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 1 <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">f</i> to 20 <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">f</i> was carefully investigated. Numerical and experimental results both demonstrated that a metasurface of phase profile at 5 <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">f</i> is extremely powerful in distributing the scattering energy more uniformly than a metasurface of 1 <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">f</i> 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°. 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.