Broadband Linear-Phase Metasurface for Full-Polarization Cloaking With RCS-Reduction Capability

Traditional co-polarized metasurface cloaks suffer from limited bandwidth, polarization sensitivity, and mismatched operating bands between near-field (NF) and far-field (FF) responses. To overcome these limitations, this work proposes a linear-phase metasurface cloak whose phase response follows the linear law required for broadband cloaking. The cloak is realized using anisotropic unit cells with an 8-mm periodicity and 4-mm thickness, both determined through systematic parametric studies. Surface-current analysis and multi-frequency NF simulations validate its wideband performance. A spin-decoupling strategy is further introduced to enable joint cloaking under both linear and circular polarizations (LP/CP). Multi-frequency experiments under normal incidence demonstrate efficient LP/CP cloaking over a 6.5–10.5 GHz band (47% fractional bandwidth), with a flat 4 dB FF RCS reduction under representative LP excitation across the same frequency range, exhibiting well-aligned NF and FF operating bands without performance trade-offs.