Due to the mirror symmetry breaking, chiral structures show fantastic electromagnetic (EM) properties involving negative refraction, giant optical activity, circular dichroism and asymmetric transmission. Aligned electric and magnetic dipoles excited in chiral structures contribute to the extraordinary properties. However, the chiral structures that exhibit n -fold rotational symmetry show a limited tunability of the chirality. In this paper, we propose a compact, light, and highly tunable anisotropic chiral structure to overcome this limitation and realize a linear-to-circular polarization conversion. The anisotropy is due to simultaneous excitations of two different pairs of aligned electric and magnetic dipoles. The 3-D omega-shaped structure, etched on two sides of one printed circuit board (PCB) with connecting metallic vias, achieves 60% of linear-to-circular conversion (transmission) efficiency at the operating frequency of 9.2 GHz. The desired 90° phase shift between the two orthogonal linear polarizations is not only from the chirality but also from the anisotropic chiral response slightly off the resonance. The work enables elegant and practical polarization control of EM waves.


Electrical and Computer Engineering


National Natural Science Foundation of China, Grant 61271158

Keywords and Phrases

Chiral structure; circular polarizer; polarization control

International Standard Serial Number (ISSN)


Document Type

Article - Journal

Document Version


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Publication Date

01 Nov 2016