Efficient multiband and broadband cross polarization converters based on slotted L-shaped nanoantennas

In this paper, we presented highly efficient reflective cross polarization converters based on metamaterials operating in the infrared regime, which are composed of a dielectric spacer sandwiched between slotted L-shaped metallic nanoantennas and a ground plane. The proposed polarization converters can convert a linearly polarized wave to its cross polarized wave with high polarization conversion ratio (> 0.95) over multiple / broad frequency bands. The resulting multi-band and broadband operations are induced by the localized mode hybridizations between the slot and the original metallic nanoantenna. Furthermore, the performance of the proposed converters under different incident angles is also explored. It is found that the first broad band (or the first two resonant frequencies) of the proposed broadband (or multi-band) converters appears to be independent of the incident angle (up to 47°).