Semi-transparent magnetic metasurface screens with modulated impedance for mitigation of radiation in the shadow domain

Abstract

The paper proposes vertically oriented, semi-transparent metasurfaces to suppress radiation from a source in it’s shadow region. These metasurfaces consist of small metallic loop meta-atoms with lumped capacitors, designed such that their magnetic polarization is perpendicular to the incident wave. Semi-transparency is achieved by employing Fano resonance of total reflection, while undesired full transparency resonance is avoided by adjusting the capacitor placement. The metasurfaces admittance profile is analytically synthesized using geometrical optics for large source distances and numerically optimized for practical scenarios with smaller screens and closer source distances. Simulation results demonstrate up to 20 dB radiation suppression across the entire shadow region for screen sizes near 2λ and source distances around 0.5λ, without reducing the gain in the lightened domain.