In-Band RCS Reduction of Circularly Polarized Antenna Array with High Aperture Efficiency and Low Profile for Satellite and Navigation Systems

This paper proposes a circularly polarized (CP) antenna array featuring high aperture efficiency, a low in-band radar cross section (RCS), and a low profile. First, two different patch antenna elements are designed, which exhibit desirable CP performance and a 180° reflection phase difference under x-polarized normal incidence within the same operation band. These elements are then arranged in a chessboard configuration to simultaneously achieve high aperture efficiency and in-band RCS reduction under x-polarized normal incidence. Subsequently, the parasitic units are uniformly embedded into the array elements, which are employed to realize reflection phase cancellation with the array elements under y-polarization normal incidence. The simulated results show that the proposed array achieves a peak monostatic RCS reduction of 12.8 dB, and the 6 dB RCS reduction bandwidth fully covers the antenna’s operating bandwidth under both x- and y-polarized normal incidences. Moreover, the gain of the antenna array reaches 18.2 dBic at 3 GHz with an aperture efficiency of 58% and a profile of 0.03λ. A good agreement is obtained between the simulated and measured results. This design successfully combines the advantages of high aperture efficiency, dual-polarized in-band RCS reduction, and a low profile, making it highly valuable for aerospace satellite communications and unmanned aerial vehicle data links.