A Novel Wideband and High-Efficiency Electronically Scanning Transmitarray Using Transmission Metasurface Polarizer

Inspired by the recent progress of metasurfaces, a novel wideband and high-efficiency electronically reconfigurable transmitarray (TA) is presented that can enable two-dimensional (2-D) beam steering and multiple beam mode switching in a digital manner. The proposed unit cell consists of a reconfigurable anisotropic metallic resonator, which locates between a pair of orthogonally oriented subwavelength metal gratings. One-bit phase quantization is obtained by controlling the ON or OFF state of two positive-intrinsic-negative (p-i-n) diodes integrated on the anisotropic metallic resonator layer. To choke the radio frequency (RF) signal effectively, a bias layer is connected by the metallic via hole to the center of the resonator, where the electric field is minimal. The simulated results show that the proposed unit cell can achieve a low insertion loss of 1 dB from 9.3 to 10.9 GHz for two phase states. Then, the radiation performance of a 10 $\times\,\,10$ element array fed by a pyramidal horn antenna is theoretically calculated, simulated, and measured. The measured maximum gain is 19.1 dBi at 10.0 GHz with an aperture efficiency of 25.8% and a 3 dB gain bandwidth of 15.9%. The measured results demonstrate the 2-D beam scanning capability within the 50° range.