Polarization-Independent Ultra Wideband RCS Reduction Conformal Coding Metasurface Based on Integrated Polarization Conversion-Diffusion-Absorption Mechanism

Abstract

An ultra wideband (UWB) radar cross-section (RCS) reduction metasurface has received attention in recent years. However, the majority of the research has concentrated on the physics and design of planar surfaces, which do not meet the standards of modern aerodynamics and aesthetics. In this paper, we offer a sophisticated strategy for designing a metasurface that can conform to the shape of any object, even those of moderate curvature, and can also achieve UWB RCS reduction by combining absorption, polarization conversion, and diffusion mechanisms. Firstly, an absorbing-polarization converter is designed, composed of a square patch with a truncated diagonal strip and ring. A thin Rogers RT/Duroid 5880 dielectric substrate layer is used in the structure, which is also appropriate for conformal conditions. The substrate layer and the ground plane are separated by an air gap to enhance the polarization conversion bandwidth (PCBW). For normal incident electromagnetic (EM) waves, the PCBW ranges from 10.8 to 31.3 GHz with polarization conversion ratio (PCR) values greater than 0.9 dB. Up to a 45∘ oblique incidence angle over the aforementioned band, the PCR efficiency is well maintained. Then, the optimized coding metasurface is formed by the Pancharatnam–Berry (PB) phase, consisting of meta-atoms “0” and “1” of the same size but different orientations, to realize the concept of cross-polarization diffusion. A theoretical investigation has been performed to analyze the RCS reduction performance of planar as well as conformal cylindrical surfaces. The results show that more than 10 dB of RCS reduction is experienced over UWB (10.8–31.3 GHz) for planar metasurfaces under linearly and circularly polarized incidence waves. Furthermore, the RCS reduction for cylindrical surfaces can be achieved in a similar frequency band above 10 dB up to an angle of 90∘. It can be deduced that our proposed flexible metasurface can be used as an absorber or a polarization converter and provide broadband RCS reduction, which is essential for multi-function and conformal stealth applications.

Transparent conformal metasurface absorber for ultrawideband radar cross section reduction

“…Stealth technology is one of the most promising applications for MS absorbers (MSAs) [6]. Lowering the radar cross section (RCS) of military applications is a key component of stealth technology, which is used to evade detection by hostile radar [7,8]. Multilayer structures or frequency reconfigurable lumped elements are commonly used in the development of MSA for RCS reduction in broadband [9][10][11][12][13].…”

Ultra-wideband and wide-angle RCS reduction of a concave structure based on a chessboard polarization conversion metasurfaces

“…Thus, it is essential to achieve the RCS reduction of the curved surface structure in order to considerably reduce the aircraft's backward electromagnetic scattering and improve the target's combat survivability. The majority of the studies on RCS reduction of curved structures [4][5][6][7][8][9][10][11][12][13][14][15][16][17][18] that are currently available focus on convex structures [4][5][6][7][8][9][10][11][12][13][14][15], while concave structures [16][17][18] have received limited attention in previous studies. Ishii et al using a concave metasurface absorber, achieved a −10 dB RCS reduction at 9.88 GHz under normal incident [16].…”

A conformal coding metasurface for dual polarization conversion and radar cross section (RCS) reduction

“…Thus, flexible and nonplanar metasurfaces offer researchers a new avenue of study and have garnered considerable interest. Recently, a few efforts aimed at lowering the RCS of conformal structures have been published in the literature [31][32][33][34]. Nevertheless, these metasurfaces are restricted to a single functionality or working band that restricts their use in modern-day compact devices.…”