RCS reduction characteristics of thin wave absorbers composed of flat and curved metasurfaces

摘要

Thin wave absorbers composed of a periodic structure of metal patches have been investigated in order to reduce the radar cross section (RCS). To achieve stable operation for absorbing frequency at oblique incident angles, a high value of permittivity of the substrate or a very thin substrate are required. This paper presents the RCS reduction characteristics of a metasurface absorber with 0.1-mm thickness at oblique incident angles. The calculated result indicates that the RCS reduction of the flat-wave absorber near 10 GHz is 16 dB at normal incidence, and experimental results show a 10-dB reduction. The RCS of the curved wave absorber is attenuated by 11 dB. The transverse magnetic (TM) incident wave pattern shows steady RCS reduction characteristics at oblique incident angles. In contrast, the transverse electric (TE) incident wave pattern shows that the attenuated frequency becomes low and RCS reduction decreases as the incident angle increases.