From Metasurface to Low-RCS Array Antenna: A Fast and Efficient Route to Design Stealthy Array Antennas

In the conventional routes to obtain stealth array antennas, various techniques are used to reduce the radar cross sections (RCSs) of existing antennas based on experience-relying trial-and-error and time-consuming optimizations. To address the issue, we propose reverse thinking, i.e., low scattering performance precedes radiation performance, and present a universal and definite route to achieve low-RCS array antennas directly from metasurfaces rather than from antennas. A specific design method is carefully elaborated to illustrate this route. First, a low RCS metasurface is designed. Then an interdigital arrangement of the metasurface and proper feeding techniques are exploited to excite parts of the metasurface cells to produce efficient radiations. These partially excited cells play twofold roles as the radiating structures for array antenna and as part of scattering structures for the low-RCS property. As examples, 1-D and 2-D metasurface-based array antennas are elaborately designed and fabricated, in which good radiation performance and broadband low RCSs are achieved simultaneously. Both numerical simulations and experimental results verify the effectiveness of the proposed method. It suggests that the proposed route is more likely to speed up the design process and yield an integration structure and controllable performance.