Wide-angle retroreflector engineered with an angle-insensitive, broadband reconfigurable metasurface

Current metasurface retroreflectors are often constrained by narrow bandwidths, limited angular performance, and confinement to one-dimensional operation, which hinders their integration into compact electromagnetic systems. Here, we propose a reconfigurable metasurface that overcomes these limitations to achieve broadband, wide-angle, and two-dimensional (2D) retroreflection for both TE and TM polarizations. The design strategy integrates varactor-loaded meta-atoms for continuous dynamic phase tuning with a metallic via-fenced topology. This configuration creates decoupled resonant cavities that effectively suppress spatial dispersion and mutual coupling, ensuring robust angular stability even under highly oblique incidence. The simulated results demonstrate that the proposed metasurface achieves a continuous reflection phase tuning range exceeding 315° across a broad operational bandwidth from 3.25 to 6.72 GHz. Experimental measurements of a fabricated prototype further validate that the metasurface realizes high-efficiency, low-side-lobe retroreflection over a wide 2D incidence range up to 60°. With its combination of wide-angle robustness, full-polarization compatibility, and dynamic reconfigurability, this device provides a promising platform for advanced radar systems and next-generation wireless communications.