High-Efficiency Wideband Single-Substrate Layer Linear-to-Circular Polarization Converter Based on Huygens’ Metasurface

High-efficiency wideband linear-to-circular polarization converters (LCPCs) attract extensive attention from engineers. However, the mechanism contributing to their high efficiency is seldom reported. In this article, a high-efficiency wideband transmissive LCPC with high angle stability based on a single-layered Huygens’ metasurface (MS) is proposed. Leveraging Huygens’ principle, the electromagnetic response and current distribution of the proposed LCPC indicate that the generation of Huygens’ resonances fundamentally drives the high-efficiency property. At the Huygens’ resonance frequency, both electric and magnetic responses can be excited, resulting in near-unity transmission amplitude. The experimental results confirm that the proposed LCPC achieves high-efficiency transformation from linearly polarized (LP) wave to circularly polarized (CP) wave within the operating band of 16.3–31.7 GHz, achieving a 3-dB axial ratio bandwidth (ARBW) of 64.2%. Additionally, the LCPC exhibits a high LP-to-CP transmission coefficient (TC) of up to 0.96 and maintains a high angle stability for oblique incidences up to 45°.