Planar Phase Gradient Metasurface Antenna With Low RCS

A low radar cross section (RCS) planar antenna using phase gradient metasurface is proposed in this paper. The proposed antenna works in the ${X}$ -band and is fed by a parallel plate waveguide power divider. The designed phase gradient metasurface is coplanar with the feeding structure and couples guided waves in the parallel plate waveguide power divider to radiation waves. According to the generalized reflection law, the proposed metasurface is a frequency scanning antenna and the beam direction can be steered slightly from 16.6° to 13°. The proposed antenna is linearly polarized, and however, the RCS is reduced significantly for arbitrary polarized incident waves. The antenna was simulated, fabricated, and measured. The measurement results confirm well with the simulation results.