Ultra-wideband and large-range incident angles radar cross-section reduction by quasi-fractal polarisation conversion metasurfaces

This study proposes a quasi-fractal polarisation conversion metasurface (PCM) for ultra-wideband radar cross-section reduction (RCSR). The simple and proposed metasurface is composed of double-heads arrowed-like unit cell benefited from the second iteration Koch fractal in its arm and cut-line to broaden the bandwidth. Consequently, this PCM unit cell and its 90, 180 and 270 degrees rotated counterparts obtain destructive interference cancellation between their reflected waves and RCSR. The proposed metasurface demonstrates 10-dB RCSR from 7.68 to 40.87 GHz (136.73%) for normal incident waves, and more than 96.7% up to 40 degrees incident angle that verifies the large range incident angle RCSR of the surface. The experimental measurement results at the normal incident angle and their comparison with simulation ones prove the idea.