  A simple but efficient approach for the synthesis of transmission-type
wideband polarization converters is presented. The proposed configuration
comprises multilayer metasurfaces including resonant particles which are
progressively rotated layer by layer. The progressive rotation of the particles
allows for a polarization conversion over a large frequency band. The
polarizing structure is efficiently designed and optimized through a
transmission line model approach handling the cascade of anisotropic impedance
layers and dielectrics. An optimized 8-layers design based on gradually rotated
dipole resonators is presented as a proof of concept. The results obtained
through the efficient transmission line model are compared with full-wave
simulations once that the structure was optimized showing satisfactory
agreement. A prototype of the wideband polarization converter has been
fabricated and measured.
