Passive‐Active Joint Metasurface for Integrated Stable and Dynamic Electromagnetic Manipulations

Most studies on metasurfaces have been focused on either programmable active schemes for dynamic and multifunctional electromagnetic (EM) manipulations or passive schemes with fixed functionalities for a low‐power solution. Such methods have their inherent advantages in different application scenarios. However, combining the active and passive EM manipulations in the same aperture is still challenging due to the complicated metasurface design. Here, we propose a passive/active joint metasurface with both fixed phase response and programmable features in the same meta‐atom, providing a solution to the integrated stable/dynamic EM manipulations. By introducing geometrical variation and varactor‐based real‐time modulation simultaneously, the metasurface can achieve 1‐bit phase coding in the passive mode and 2‐bit programmable phase coding and polarization conversion in the active mode. To validate the function of the metasurface, we conduct simulations of the meta‐atom and meta‐array and realize a prototype for measurement, achieving the integration of dynamic beamforming and stable radar cross‐section reduction. The simulation and experiment results show that the proposed metasurface provides a prospect for passive/active design in complex EM environments and has application potential in low‐cost reconfigurable intelligent surfaces, target tracking with EM stealth, and others.