Design of a broadband radiation and scattering integrated circularly polarized slotted array antenna

This paper proposes a broadband circularly polarized low radar cross section (RCS) slot array antenna incorporating a polarization conversion metasurface (PCM). First, a PCM unit comprising two dielectric substrates and three metallic patches is designed to achieve wideband cross-polarization conversion. A checkerboard PCM structure is constructed with optimized unit arrangement to obtain wideband RCS reduction. Based on this PCM, single-element and four-element array antennas are designed. Communication performance is enhanced through microstrip slot coupling feed. Simulation and physical testing validate the design’s effectiveness. Simulation results indicate the array antenna exhibits impedance bandwidth from 4.61 to 9.44 GHz, peak gain of 11.82 dBi, and axial ratio bandwidth from 5.82 to 8.43 GHz. It achieves RCS reduction exceeding 10 dB across the 6.71 to 17.88 GHz band, with a relative bandwidth of 90.8%. Finally, physical fabrication and testing validated the accuracy of the simulation results. This antenna combines broadband communication capabilities with low RCS characteristics, making it suitable for scenarios requiring both electromagnetic stealth and communication performance.