In-Band RCS Reduction and Gain Enhancement for a Patch Antenna Array by Using a 1-D Periodic Metasurface Reflector

A low-profile metasurface (MS) with low scattering performance for both the x- and y-polarizations is designed based on far-field cancellation. Different from a conventional MS with a low radar cross section that uses chessboard structures, this design makes use of a 1-D MS. Without requiring periodicity in two dimensions, the proposed MS can thus be integrated more flexibly in many applications. Based on the proposed MS, a patch antenna array is proposed. Full-wave simulations and measurements show that, by incorporating the proposed MS, the scattering of the antenna array can be reduced by more than 5 dB over the antenna operating frequency band from 10.7 to 12 GHz (11.45%) under normal incidence. Furthermore, when the array radiates, parasitic radiation can be excited from the slots of the MS, which enhances the boresight gain of the array.