Effective Broadband RCS Reduction in Metasurfaces through Composite Vortex Phase Modulation

Inspired by the concept of orbital angular momentum (OAM), this article introduces an innovative and effective technique for achieving broadband reduction of radar cross section (RCS) in metasurfaces. By introducing the controllable phase transition along the radial direction within the vortex phase distribution, and combing this with the annular segmentation regions of the metasurface, the local manipulation of the beam intensity and topological mode distribution is realized, thereby generating composite vortex beams. These beams not only retain the phase singularity property, which contributes to a significant reduction in the RCS of the metasurface along the propagation axis, but also effectively redirect scattered energy into non-threatening angular domains, thereby further reducing the bistatic RCS of the metasurface. Furthermore, the Pancharatnam-Berry (PB) phase is utilized to encode the phase profile of the metasurface, and this phase is only related with the rotation angle of the unit-cells, thereby enabling the composite vortex metasurface to exhibit broadband response characteristics. Simulation and experimental results demonstrate that, within the frequency range of operation from 12.3GHz to 23.8 GHz, the designed metasurface achieves monostatic and bistatic RCS reduction values exceeding 10 dB under normal incidence of plane waves with either circular polarization or linear polarization. Additionally, when the plane wave is incident at an oblique angle less than 45°, the metasurface retains a good performance of RCS reduction. © 2026 IEEE.