Near-Field Shaped Focusing Based on 1-Bit Coded Tensor Holographic Impedance Metasurface

In this paper, a shaped near-field is generated by 1-bit coded holographic impedance metasurface (HIMS), and a method to calculate the impedance distribution of holographic impedance surface is proposed by using time inversion, which can realize near-field shaping focusing under arbitrary polarization. The designed gated grid tensor unit adopts 1-bit encoding on the rotation angle, only 0° and 90°. The designed tensor holographic impedance metasurface, operating at 18 GHz, can produce right-handed circularly polarized square near-field focusing shapes. The measured and simulated results are consistent, showing that the designed metasurface has a square shape under the right-handed polarization component of the near-field electric field, and the focusing efficiency of the metasurface can reach 63.3%, which verifies the effectiveness of the method.