| Abstract: | An ultra-thin metamaterial absorber with polarization stability, a wide incident angle and no surface ullage layer is proposed and applied to the waveguide slot antenna to reduce its in-band Radar Cross Section(RCS). Theoretical analysis, and simulation and experimental results demonstrate that the absorber can exhibit an absorption of 99％ with thickness of only 0.0057λ, that when applied to the waveguide slot antenna in an optimized distribution, it can reduce the in-band RCS of the antenna for more than 3dB from -21° to +21°, that the largest reduction value exceeds 13dB in the normal direction, and that it can increase the gain by 0.99dB. |
