Ultra-wideband tunable reflective linear-to-circular polarization converter realized by GST-based metasurface at terahertz frequency

Polarization conversion of electromagnetic wave plays an important role in practical application. In this paper, a terahertz band ultra-wideband tunable linear-to-circular polarization converter based on GST metasurface is proposed. It consists of two triangular metals, a phase change material (GST), a dielectric plate and a metal floor. The proposed polarization converter can convert linearly polarized waves into circularly polarized waves in different frequency bands by controlling the crystallization state of GST through temperature, without the need of re-optimization and remanufacturing structure. It has the characteristics of ultra-wideband and high efficiency. The proposed polarization converter has potential for miniaturization and integration of terahertz systems.