A Pure Water Linear-to-Circular Polarization Converter

A linear-to-circular (LTC) polarization converter utilizing pure water is investigated in this paper, which has advantages of high transparency and shorter transmission length due to the very high dielectric constant of pure water. It is made of periodic water slabs surrounded by 3D printed dielectric containers. The printing material used is photosensitive resin which has a high transparency to ensure the whole converter being an optically transparent structure. By choosing proper dimensions of the water slabs, an incident linearly polarized plane wave which has a 45-degree angle with the water slabs will pass through the converter, resulting in circular polarization (CP) of the transmitted waves due to the different travelling speed of two orthogonal electric components decomposed by the incident wave. A water slab LTC polarization converter is designed to verify the performance. Simulated results indicate that a 3-dB axial ratio (AR) band of 33% is achieved with a transmission length of $\mathbf{0.13\ \lambda_{0}}$.