High-efficiency Huygens' surfaces for electromagnetic wave controlling

A Huygens' surface that efficiently refracts normally incident electromagnetic waves at 12 GHz is reported. The phase gradient along the interface is modulated by four isotropic, non-resonant, spatial phase shifters with dimensions of 0.5λ
₀
× 0.5λ
₀
, where λ
₀
is the free-space wavelength at 12 GHz. The electric and magnetic responses of the unit cells are controlled by metallic patterns etched on multilayer dielectric substrates. Then, these surface structures are used to fabricate a high-efficiency microwave lens with F/D to be 0.27. The simulation results show that the peak value of the transmission efficiency approaches 97.6%.