Dual-polarized metasurface design enabled by characteristic mode theory: integrated synergistic radiation and scattering functions.

Synergistic radiation-scattering integration holds great value for secure communication, electromagnetic stealth, and anti-interference wireless systems. Nevertheless, the intrinsically incompatible electromagnetic responses of radiation and scattering complicate the pursuit of a satisfactory trade-off in their collaborative co-design. Leveraging characteristic mode theory (CMT), this paper proposes an automated topology optimization strategy to facilitate the high-efficiency design of dual-polarized radiation-scattering integrated metasurfaces. The radiation and scattering responses of the metasurface are formulated into objective functions based on characteristic mode parameters, enabling high-performance broadside radiation and simultaneous phase and polarization modulation of the scattered field. With the aid of the non-dominated sorting genetic algorithm-II (NSGA-II), a programmable metasurface unit cell loaded with PIN diodes is designed and periodically arranged into an orthogonally configured array. The resultant metasurface realizes dual-polarized radar cross-section (RCS) reduction via scattering and polarization cancellation mechanisms, together with dual-polarized beam-scanning capability across the X-band. The proposed design methodology provides a powerful, universal solution for the automated design and performance optimization of radiation-scattering integrated metasurfaces.