Reconfigurable Planar Huygens' Metasurface for Wide Beamforming

Huygens' metasurfaces (HMSs), which independently control electric and magnetic dipole responses, have been implemented in planar platforms. However, dynamically controlling both dipole responses to achieve reconfigurability at the sub-wavelength scale remains challenging with conventional planar HMSs. In this work, these challenges are addressed by introducing the first planar, reconfigurable HMS design that integrates varactors and embedded bias lines, allowing for precise and independent control of electric and magnetic surface impedances at the sub-wavelength scale (lambda(0)/9.4 x lambda(0)/6.3 x lambda(0)/22.7) at 5.5 GHz. A large-aperture HMS (4.47 lambda(0) x 4.47 lambda(0)), integrated with 3,528 varactors and fed by a 4 x 4 patch array at a focal-length-to-diameter ratio of 1.6, demonstrates wide beamforming angles ranging from -70 degrees to +70 degrees with an aperture efficiency of 21.09%. This innovative design offers a promising solution for efficient and compact reconfigurable intelligent surfaces, paving the way for advanced wave control in next-generation wireless communication and sensing applications