Loading metamaterial perfect absorber method for in-band radar cross section reduction based on the surface current distribution of array antennas

A loading metamaterial perfect absorber (MPA) method is proposed to reduce the in-band radar cross section (RCS) and preserve the radiation characters for the guidewave slot array antennas in this study. The surface current distributions of the array antennas are divided into the strong current area and the weak current area. The metal surface with the strong current is retained to avoid the radiation deterioration, and the MPA is only loaded on the weak current area by the three layers MPA for RCS reduction. The RCS of a 1 × 10 guidewave slot array antennas is reduced using the method. Simulated S₁₁, radiation patterns, gain and RCS reduction of the array antennas are compared with measured results. Experimental results indicated that the in-band RCS of the array antennas loading the MPA has dramatically reduced with only about 0.73 dB gain reduction and the RCS reduction are not significant in out-of-band while the radiation characters is unchanged. The experimental results are in good agreement with the numerical simulations.