A Low RCS Millimeter-wave Antenna Based on Frequency Selective Absorber

In this work, a low RCS millimeter-wave antenna based on FSA is proposed, achieving dual function with wideband radiation and out-of-band absorption. The proposed structure comprises a top-layer of FSA structure and a bottom layer of millimeter-wave antenna. With the addition of the FSA layer, the proposed antenna absorbs incident waves under arbitrary polarizations in the frequency range of 8-21 GHz. Notably, the proposed antenna maintains effective radiation in the frequency range of 21-27 GHz. Consequently, the proposed antenna achieves broadband low out-of-band RCS performance, which exhibit its potential practical utility in millimeter-wave communication and radar safeguard.