Gain Enhanced Circularly Polarized Antenna With RCS Reduction Based on Metasurface

In this paper, a gain-enhanced circularly polarized (CP) patch antenna with in-band and out-of-band radar cross section (RCS) reduction is designed, fabricated, and analyzed. Both the proposed and reference CP patch antennas are etched with truncated corners and designed to operate at 8.2 GHz, while the proposed antenna is surrounded by chessboard arrangement of an ultra-wideband and high-efficiency polarizer that can rotate linearly polarized incident waves into the orthogonal one ranging from 7.55 to 20.74 GHz. Meanwhile, the polarization conversion ratio remains higher than 0.9 within the operating band. The simulation results show that the realized gain of the proposed antenna is enhanced by 2.5 dB at 8.2 GHz, and 11 dB average RCS reduction is achieved within the operating band (7.55-20.74 GHz). The working mechanism of the simultaneous realization of gain enhancement and RCS reduction is analyzed in detail. Finally, the designed and reference antennas are fabricated and tested, which demonstrates the effectiveness of the proposed design method. The proposed antenna can be potentially applied in a future communication device and stealth platform.