Evaluation of a Dual-Circularly-Polarized Reflective Metasurface as a Plane Wave Generator in Ka-Band

In this work, a reflective metasurface is designed to generate a dual-circularly-polarized uniform plane wave at Ka-band (31 GHz). The metasurface is designed using a Phase-Only Synthesis with the generalized Intersection Approach. The design considers tight constraints in both amplitude and phase of the radiated near field. The synthesized phase-shift distribution is also used to convert the dual-linearly polarized incident field into a dual-circularly polarized reflected field. The unit-cell of the metasurface is based on two stacked layers of three parallel dipoles, adjusted cell by cell to provide the synthesized phase distributions with less than +/- 1 degrees of phase error. Preliminary results show the generation of a uniform plane wave in an area equivalent to 82.8% of the metasurface aperture size, revealing the possibility of generating dual-circularly-polarized uniform plane waves using metasurfaces with a simple design process.