Chessboard-Coding Metasurface for Wideband RCS Reduction Under Wide Angle of Incidence

• A simple profile circle-shaped unit cell is designed, which performs polarization conversion in the frequency band of 17.6 to 41 GHz. The unit cell, along with its mirror, will have a phase difference of 180 ± 37°. • The circle-shaped unit cell is arranged in a chessboard coding metasurface(CCMS), which contributes 1-bit coding in the upper quadrant and chessboard arrangement in the lower quadrant, and is analyzed for RCS reduction. • The CCMS is found to be effective in the frequency range of 9 GHz-38.8 GHz by contributing 124% fractional bandwidth. • The RCS reduction is found to be stable up to 75ᶱ oblique angle incidences. • An individual chessboard and 1-bit coding metasurface array is also investigated, which is found to be less effective than the CCMS array. A single-layer ultra-wideband metasurface based on a combined chessboard and coding metasurface (CCMS) is designed for radar cross-section (RCS) reduction, utilizing the principles of polarization conversion and destructive interference. The CCMS array is composed of the coding metasurface in the upper quadrant and the chessboard metasurface in the lower quadrant, redirecting the incident electromagnetic wave (EM) into numerous wide angles. The unit cell is circular-shaped with a symmetrical slot, thereby achieving a 90% polarization conversion ratio (PCR) between 17.6 to 41 GHz frequency range. By exploiting the proposed unit cell, the CCMS arrangement has obtained 124% fractional bandwidth and angular stability of 75° in the frequency range of 9 GHz-38.8 GHz. The metasurface shows strong angular stability for off-normal incidences, up to an incidence angle variation of 75°. For both normal and oblique incidences, the simulated results agree well with the measured results of the designed prototype. Further, the proposed results are compared with an individual chessboard metasurface and a 1-bit coding arrangement, which is found to be less efficient than the proposed CCMS.