A Broadband and Wide-Angle R-KR Lens Retrodirective Array

This letter presents a novel radar cross section (RCS) enhancement structure: a dual R-KR lens retrodirective array (LRDA). A single R-KR LRDA is first designed by utilizing the broadband and wide-angle beam scanning capabilities of the R-KR lens. However, this configuration exhibits significant monostatic RCS fluctuations across the angular range, as observed in the simulation results. An analysis of the field distribution identifies the primary causes of these fluctuations. To address this issue, a dual R-KR LRDA is proposed, in which two single R-KR LRDAs are arranged in a parallel, laterally staggered configuration. Simulation and measurement results indicate that the dual R-KR LRDA achieves a maximum monostatic RCS fluctuation of approximately 3 dB over an angular range of ±55° within the frequency range of 8.1-12 GHz under linearly polarized (LP) incidence, demonstrating enhanced retrodirective performance.