Ultra-wideband low-RCS high- and stable-gain Fabry–Perot antenna based on hybrid metasurfaces

Abstract In this paper, an ultra-wideband, low-scattering, and stable-gain Fabry–Perot antenna is proposed based on a novel hybrid metasurface. The radar cross-section (RCS) reduction is achieved by employing a 1-bit checkerboard polarization conversion metasurface (PCM) with a high polarization conversion ratio. Moreover, to enhance the antenna gain, broaden the 3-dB gain bandwidth, and maintain stable gain performance within the passband, a nonuniform reflective metasurface with a positively sloped reflection phase is strategically introduced. This metasurface, combined with the tessellated PCM layer, forms a hybrid structure featuring high transmission efficiency. Benefiting from this hybrid metasurface design, the antenna demonstrates a maximum gain enhancement of 4.7 dBi, an average gain improvement of 2.7 dBi, and a 39.8% increase in the 3-dB gain bandwidth. To validate the proposed design methodology, a prototype antenna was fabricated and experimentally measured. The measured results show good agreement with the simulated predictions. Specifically, the fabricated antenna exhibits a –10 dB impedance bandwidth of 22.47% (7.23–9.06 GHz), a 3-dB gain bandwidth of 18.2% (7–8.4 GHz), and a maximum gain of 17.25 dBi at 7.2 GHz. Additionally, the antenna achieves an RCS reduction bandwidth of 102.3%, with a maximum RCS reduction of 35.3 dB at 13.03 GHz.