Wideband RCS Reduction of a Slot Array Antenna Using a Hybrid Metasurface

A slot array antenna integrated with a hybrid metasurface (HM) for wideband monostatic and bistatic radar cross section (RCS) reduction is proposed in this article. The HM consists of an anisotropic frequency-selective absorber (AFSA) and a polarization rotation reflective surface (PRRS). The proposed AFSA absorbs the electromagnetic wave for one polarization while letting the cross-polarized wave pass through. When putting the PRRS under AFSA, the cross-polarized wave will be reflected by the PRRS with 90° polarization rotation and then the reflected wave will be absorbed by AFSA. Thus, both the co-polarized and cross-polarized incident waves are absorbed by HM. Because the incident energy is absorbed rather than reflected to the other directions, both the monostatic RCS and bistatic RCS are reduced in a wide frequency band. In addition, since the radiation wave emitted by the slot array antenna will not be reflected by the PRRS, the proposed antenna has a reasonable gain. The simulated results show that both the monostatic RCS and bistatic RCS of the proposed slot array antenna are significantly reduced in the frequency range from 6 to 18 GHz and the gain decreases about only 0.8 dB when compared with the reference antenna. The measured results are in good agreement with the simulated ones.