0.6-40 GHz RCS Suppression in a Metantenna Array Using Hybrid Scattering Control Mechanisms

The antenna module is one of the main scattering sources in low-observable platforms. Its radar cross section (RCS) needs to be suppressed in ultra-wideband to avoid detection by enemy radars in arbitrary unknown frequencies. To this end, we propose a metantenna array with excellent performance to reduce both monostatic and bistatic RCSs in ultra-wideband by using five different scattering control mechanisms. The proposed array mainly comprises a set of spoof surface plasmon polariton (SSPP) elements, resonant absorption (RA) units, and a joint polarization and phase control surface. Specifically, various types of meta-structures in the array can respond to the reflective amplitude, dispersion, polarization, and phase behaviors of electromagnetic waves in different sub-bands, thus expanding the bandwidth of RCS suppression significantly. In addition, double decoupling between the functional frequency domain and the operational electromagnetic signature domain in each mechanism ensures low mutual interference, and allows for efficient integration. More importantly, the simplified structural design can reuse not only partial scattering mechanisms, but also the radiation/scattering functions, effectively reducing the overall complexity. A 6 × 6 antenna array is fabricated to verify the performance. Measured results show that the radiation bandwidth is from 3.7 to 3.9 GHz, with the maximum in-band gain of 16.4 dBi and the minimum side-lobe level of –19.7 dB. Compared to a metal plane with the same size, the maximum RCS suppression band is from 0.6 GHz to 40 GHz (66.7: 1), with an average reduction of 13.18 dB.