Generating Arbitrary Shaped Near-Field With Arbitrary Polarization by Combining Tensor Holographic Impedance Metasurface and Phase Conjugation Techniques
Hui‐Fen Huang, Zi‐Yi Xiang
Abstract
This paper innovatively proposes combining the favorable features of Tensor Holographic Impedance Metasurface (THIMS) (flexible polarization) and Phase Conjugation (PC) (arbitrary shaping and polarization) to flexibly design THIMS, which has the ability of generating arbitrary shaped near-field with arbitrary polarization without increasing cost, structural and calculating complexity. The THIMS unit cell is modulated by two degrees of freedom: geometry parameters θt (metal patch rotation angle) and g, which solely determine the current direction and the unit cell impedance, respectively. The design scheme of continuous surface impedance value and two direction unit cells (θt = 0° or 90°) is used to design high-efficiency THIMS. Two examples are designed: (1) A right hand circular polarization (RCP) square “▪” shaped near-field with size 32 mm×32mm at 18GHz. (2) A linear polarized (LP) “I” shaped near-field with size 20mm×56mm at 18GHz. The designed shaped near-field has the following advantages: high focusing efficiency up to 63.3% (measured), high circular polarization (CP) conversion efficiency 95.3% and sidelobe as low as -15dB. The calculated, simulated and measured results agree well, and validate the proposed technique.