Generating Dual-Mode Dual-Polarization OAM Based on Transmissive Metasurface.

Recent advances in electromagnetic (EM) waves with helical phase wave-front carrying orbital angular momentum (OAM) has drawn great attention, since it is believed to be a promising candidate for the next generation of wireless communication technology. To make the design more practical, here, a transmissive metasurface for generating dual-mode and dual-polarization OAM has been designed, manufactured and experimentally validated. To generate EM waves carrying OAM, the element structure is well-designed and can introduce additional phase to the incident wave. The employed four-layer cascaded metasurface demonstrates a high performance of transmission and complete phase control. Dual-mode operating characterization is realized by applying the polarization-dependent physical response. Moreover, experimental results including near-field and far-field properties are conducted to validate the numerical simulations. The proposed method in this paper promotes the practical design and realization of OAM vortex waves for the next generation of wireless communication technology.