Antenna Array Design With Self-Adaptive In-Band Radar-Cross-Section Reduction and Beam Scanning

In this article, a novel antenna array with self-adaptive radar-cross-section (RCS) reduction has been proposed for the first time. The design mechanism of the proposed array is based on Van Atta retrodirective array and orbital angular momentum (OAM) vortex wave. By inheriting the adaptive beam tracking ability of the Van Atta array, the scattering beam of the proposed antenna can be automatically steered toward the incident wave direction without any prior knowledge of the incident wave. By reasonably designing the connection line lengths in the Van Atta array, the OAM scattering beam with null amplitude along the arbitrary incident direction is generated for the RCS reduction. As the demonstration, a dual-ring array with dual-polarization characteristic has been designed. By choosing a part of the antenna elements as the Van Atta array and the remaining part of the antenna elements as the radiation array, the designed antenna array can simultaneously achieve the beam steering and the low in-band RCS performance without the increase in the antenna array size. The prototype of the proposed array is fabricated, and good agreement between the simulation and the measurement verifies the proposed design.