Backscattered EM-wave manipulation using low cost 1-bit reflective surface at W-band

Abstract

The design of low cost 1-bit reflective (non-absorptive) surfaces for manipulation of backscattered EM-waves and radar cross section (RCS) reduction at W-band is presented in this article. The presented surface is designed based on the reflection phase cancellation principle. The unit cell used to compose the proposed surface has an obelus (division symbol of short wire and two disks above and below) like shape printed on a grounded dielectric material. Using this unit cell, surfaces that can efficiently manipulate the backscattered RCS pattern by using the proposed obelus-shaped unit cell (as ‘0’ element) and its mirrored unit cell (as ‘1’ element) in one surface with a 180° ± 35° reflection phase difference between their reflection phases are designed. The proposed surfaces can generate various kinds of backscattered RCS patterns, such as single, three, or four lobes or even a low-level (reduced RCS) diffused reflection pattern when those two unit cells are distributed randomly across the surface aperture. For experimental characterization purposes, a 50 × 50 mm2 surface is fabricated and measured.

Realization of Single-Layer Fourier Phased Metasurfaces for Wideband RCS Reduction

“…etasurfaces are a 2D engineered surface which can be used to manipulate the phase, magnitude, and polarization of the incident electromagnetic wave (EM-wave) and therefore achieve extraordinary functionalities such as polarization conversion [1] - [5], beam steering [6], beam focusing [7] - [8], cloaking [9]- [10]..etc. Radar cross section (RCS) and diffusion of EM waves is one of the important functions of the metasurface and has been a hot topic in the last decade [11] - [15]. Chessboard and checkerboard metasurfaces are among the first metasurfaces designs for RCS reduction [16]- [19].…”

Wideband RCS Reduction by Single-Layer Phase Gradient Modulated Surface

“…PGM have been highlighted as a good candidate for realizing electromagnetic-wave-focusing characteristics by manipulating the wavefront through controlling the spatial phase and transmission profiles of metasurfaces. Since the PGMs are able to provide pre-defined in-plane wave vectors to manipulate the directions of the refracting/reflecting waves, it consequently attracts a lot of attention in such a kind of beamforming mechanism [ 19 , 20 , 21 ] and RCSR [ 22 , 23 , 24 ].…”

Broadband RCS Reduction by a Quaternionic Metasurface

“…Different from metamaterial absorbers which directly reduce the amplitude of microwaves by absorption, metasurfaces exploit the phase modulation of gradient changing unit cells to reduce backscattering by interference [ 23 , 24 ]. Based on this idea, the unit cells of metasurfaces with different phases are coded, designed, and programmed to show highly designable scattering patterns, including the ones that show extremely low radar observability [ 25 , 26 , 27 , 28 ]. The RCS reduction metasurfaces makes use of phase difference of neighboring unit cells other than the strong resonant absorption, granting them much broader working bandwidth and lower profile with respect to metamaterial absorbers [ 29 , 30 ].…”