Design of an Optically Transparent Transmitarray Based on Huygens' Metasurface

A novel optically transparent transmitarray based on double-layer Huygens' metasurface is proposed by combining fine metal lines and optically transparent polyethylene terephthalate (PET) and cyclic olefin copolymer (COC) dielectric substrates. The top and bottom metal lines on COC substrate simultaneously function as electric and magnetic dipoles, inducing orthogonal electric and magnetic currents. At the center frequency of 33 GHz, the transmission loss and phase shift of the proposed transmitarray element are
$\sim \mathbf{0.83}\quad \mathbf{dB}$
and 334°, respectively. The transmitarray has a high gain of 25.3 dBi, leading to a high aperture efficiency of 47%.