Single-Substrate Circularly Polarized Huygens’ Metasurface With Independent Modulation of Electric and Magnetic Impedances

Huygens’ metasurfaces (HMSs) provide an effective approach for obtaining arbitrary complex amplitude by simultaneously modulating the orthogonal electric and magnetic resonances. However, independent modulation of surface electric and magnetic impedances (phase and amplitude) still remains a challenge for single-substrate circular polarized HMS. Herein, a novel strategy for achieving independent control over surface electric and magnetic impedances of circular polarization (CP) wave is proposed by using a single-substrate metasurface. The inner S-shaped patterns (SPPs) dominates the electric responses, while the outer concentric split rings (CSRs) dominate the magnetic responses. Thus, independent control over amplitude and phase is enabled by separately modulating the SSP and the CSR, respectively. It is noted that the proposed strategy could not only effectively modulate the cross-polarized CP but also the co-polarized component according to the generalized sheet transition conditions, indicating a strong universality. The concept and significance of it has been validated by implementing three proof-of-concept prototypes. The former two could generate multiple focal spots in the near-field region, and the latter one could achieve a low sidelobe-level beam in the far-field region. The proposed strategy provides a new avenue for independently controlling the amplitude and phase of CP wave, which can find applications in electromagnetic (EM) integration, wireless power transfer, and point-to-point communication systems.