A 3-D Van Atta Retrodirective Array Based on Reflection Phase Cancellation

This letter presents a novel three-dimensional (3D) passive Van Atta antenna array capable of achieving multiple polarization retrodirective functionalities, including both linear polarization (LP) and left-handed circular polarization (LHCP) responses for the first time. The array incorporates circularly polarized (CP), wide beamwidth microstrip antennas as its radiating elements. To address the issue of structural scattering fields adversely affecting the co-polarized retrodirection in conventional planar Van Atta arrays, the proposed design strategically positions subarrays comprising multiple radiating elements in different planes. By introducing appropriate height differences between these subarrays, the structural scattering fields are effectively suppressed through reflection phase cancellation, thereby enhancing the co-polarized retrodirective performance of the array. Both simulated and experimental results demonstrate that the designed 3-D Van Atta array achieves remarkable co-polarized and cross-polarized retrodirective performance for both LP and LHCP incident waves within an angular range of -30° to 30° across the frequency band of 8–12 GHz.