Broadband radar cross-section reduction using polarization conversion metasurface

Abstract

A wideband and high-efficiency polarization conversion metasurface (PCM) is proposed and applied to reduce radar cross section (RCS). The proposed PCM unit is composed of two oblique asymmetry triangle split rings, which generate multiple plasmon resonances. Simulated and measured results demonstrate that it achieves polarization conversion over 90% from 9.24 to 17.64 GHz. Besides square checkerboard, the proposed PCM units and mirror units are arranged in triangle checkerboard. The mechanisms of both checkerboard PCMs are analyzed based on standard array theory, including the relationship between RCS reduction value and polarization conversion ratio value. The derived formulas provide a guideline to design checkerboard structure based on PCM. Simulated results demonstrate that both checkerboard PCMs achieve over 62% relative bandwidth of 10 dB RCS reduction under normal incidence with respect to the equal-sized metallic plate, which also means that the triangle one could be an alternative solution to reduce RCS. To verify the analyzed and simulated results, the fabricated sample and measured results of both checkerboard PCMs are presented. Good agreements are achieved between measurements, simulations and numerical analysis.

Design of a wideband polarisation conversion metasurface and its application for RCS reduction and gain enhancement of a circularly polarised antenna

“…1d. Assuming the incident EM wave as y-polarised, the polarisation conversion efficiency can be determined using PCR as follows [16][17][18][19][20][21][22]:…”

“…The proposed PCM is composed of chessboard configuration of two PCM_a and PCM_b unit cells and according to the concept based on planar array theory, the analysis of A1 × B1 elements checkerboard metasurface has been performed. The total reflected field by the PCM can be expressed as [17,18]…”

“…Assuming the normal incident plane wave, the angles of incidence are θ = ϕ = 0°, hence for 2 × 2 PCM AF 0 = AF 1 = 1/2. For normal incident field E i , the reflected fields EF 0 and EF 1 for each PCM unit cell can be expressed as [17,18] EF 0 = R yy e j α 1co + R xy e j α 1cro E i .…”

“…Additionally, a PCM composed of triangular split rings, which can generate three plasmon resonances to obtain a PCR of 90% in the frequency range 9.2-17.6 GHz, is proposed. When compared with the same size metallic plate [18], the proposed metasurface achieves >62% relative bandwidth of 10 dB RCS reduction. Furthermore, for reducing the RCS of the slot array antenna, a PCM has been proposed by Liu et al The PCM unit cell is composed of a fish bone-shaped metallic structure and the slot array antenna is loaded with PCM arranged in the chessboard-based configuration.…”

“…In recent years, the polarisation conversion metasurface (PCM) has attracted a lot of attention, because of its numerous applications in the field of antennas [13][14][15] and researchers are more focused in developing new PCMs which can be used to reduce the RCS of the antenna [16][17][18][19][20][21][22]. Jia et al proposed a wideband polarisation rotation reflective metasurface with polarisation conversion ratio (PCR) value >50% in the frequency range of 5.98-18.84 GHz.…”