Broadband, wide-angle, polarization-independent and lightweight low-scattering coding metamaterial based on stereo meta-atoms

In this paper, by integrating the phase-cancellation and absorption mechanisms, we proposed and experimentally demonstrated a light-weight coding metamaterial for broadband, wide-angle and polarization-independent radar cross section (RCS) reduction based on stereo meta-atoms. The metamaterial is constituted by pseudo-randomly distributed two types of standing-up lossy rings as the stereo meta-atoms. Owing to the synergy of phase-cancellation and absorption, the stereo metamaterial can achieve broadband and more efficient specular RCS reduction, specifically, -10 dB RCS reduction from 7.65 to 25 GHz and over -15 dB bandwidth from 8.7 to 22.8 GHz for both transverse electric (TE) and transverse magnetic (TM) polarization under normal incidence. In addition, this metamaterial has robust RCS reduction performances against the oblique incidence for both TE and TM polarization. We fabricated a prototype of proposed stereo metamaterial by silk-screen assisted directly printing on dielectric substrate and verified its RCS reduction performances by measurement. The prototype has a light surface density as 1.3 Kg/m(2) due to the feature of hollow structure and absence of dielectric spacers usually deployed in metasurfaces. The stereo coding metamaterial we proposed has comprehensive advantages in terms of bandwidth, high efficiency, stability against oblique incidence, easy processing and light-weight for low-scattering materials.