A Planar 2-D 8×8 Van Atta Retrodirective Array for RCS Enhancement in a Wide Angular Range

Large-scale 2-D Van Atta retrodirective arrays (RDAs) typically use coaxial lines to form feeding networks, resulting in a large 3-D structure. In this study, a planar 2-D Van Atta RDA with 64 antennas and 32 transmission lines is proposed. By adding an air layer between the feeding network and the antenna array, double-layer microstrip lines can be used to realize a planar feeding network. Different types of length compensation networks are designed in limited space to eliminate the length differences between the 32 microstrip lines. Based on measured results, the Van Atta RDA works at 8.9–10.4 GHz, and the −6 dB beamwidths of the monostatic radar cross section (RCS) at 9.65 GHz are 78° (E-plane) and 90° (H-plane). Compared with the same size metal plane, the proposed Van Atta RDA has RCS enhancement of about 10–20 dB in a wide angular range.