Design of a Tri-Wideband Linear-to-Circular Polarization Conversion Metasurface*

This paper proposes a tri-wideband reflective linear-to-circular polarization metasurface. The top layer is composed of bi-directional arrow patches containing gaps of unequal lengths and widths of unequal lines symmetric about the u and v axes. Both the top patch and the bottom metal floor are copper-coated, while the dielectric substrate is made of F4B. By modifying the short arrow lines to create gaps, a wider variety of resonant modes are excited, which is advantageous for designing a tri-wideband metasurface. The dimensions of the reflective metasurface cell are 7 mm x 7 mm x 1.524 mm. The metasurface achieves 3 dB axial ratio bandwidths are 8.4-11.22 GHz (28.75%), 14.2-19.36 GHz (30.75%), and 22.52-30.1 GHz (28.81 %), achieved tri-wideband linear-to-circular polarization conversion function. Simulation results also show that the metasurface has good angular stability within 20°.