Cross-Polarization Reduction of Linear-to-Circular Polarizing Reflective Surfaces

This letter proposes an efficient design process to reduce the cross polarization of linear-to-circular reflection polarizers illuminated by practical feeds. In particular, we propose a two-step process, where first a geometrical optimization of the unit cell is applied along one plane of the reflector, followed by a progressive rotation of the unit cell in the orthogonal plane. An offset flat polarizer comprised of dipole unit cells fed by a standard gain horn has been used to illustrate the process. Significant improvements in cross-polarization discrimination are demonstrated by simulation. Two breadboards have been manufactured, and their response is compared in order to demonstrate the validity of the design process. Good agreement with measurements is observed corroborating the proposed technique.