Broadband Low-RCS Circularly Polarized Array Using Metasurface-Based Element

A novel design of broadband circularly polarized antenna array with low radar cross section (RCS) is presented. The array consists of low-profile metasurface-based elements with linear polarization. For radiation, the metasurface is excited to obtain a wide impendence-matching band. For scattering, the metasurface produces antiphase reflections under orthogonal polarized incident waves. Then, the antenna elements are orthogonally arranged in a 2 x 2 subarray and fed with 90 degrees phase shift. Based on this technique, broadband circularly polarized radiation and low-RCS feature can be achieved simultaneously. Finally, a 4 x 4 array prototype is fabricated and measured to verify our design. The simulated andmeasured results are in good agreement, addressing the confliction between radiation and scattering of antenna.