Monostatic RCS Reduction Using Broadband Reflective Metasurface in C-, X-, and Ku-Bands

Microwave stealth technology primarily focuses on the X- and Ku-band since most fire control systems work in that region. Hence, a metasurface has been presented for reducing monostatic radar cross section (RCS) in C-, X-, and Ku- bands via anomalous reflection. The proposed unit cell is a reflective linear cross-polarization converter that converts the incident polarization to an orthogonal one. The structure has a polarization conversion ratio (PCR) greater than 0.9 and an 84% relative bandwidth. Since the PCR is above 0.9, an RCS reduction of 10 dB is achieved from 6.3 to 15.4 GHz, i.e., covering the entire X band and part of the Ku and C-band. The proposed structure has been analyzed for its oblique incidence, and its PCR value is above 0.8 up to 40° incidences. An equivalent circuit model analysis has been done, and the corresponding LC parameters are obtained. The monostatic scattering of the proposed structure has been analyzed. The proposed structure has been fabricated and measured in a compact antenna test range facility, and the measured results show good agreement with the simulated results. At 10.4 GHz, the proposed structure has an RCS reduction capability of 23.4 dB with a range reduction of 74%.