Phase and Polarization Modulations Using Radiation‐Type Metasurfaces

Abstract Metasurfaces exhibit promising capacities in the manipulation of electromagnetic (EM) waves, as to diverse dimensions like amplitude, phase, and polarization; even multiple dimensions can be synchronously modulated. Despite the rapid progress in enriching regulatory capabilities of EM waves, primary feeds are integral items however bringing profile elevation, energy obstruction, and leakage, both for reflection‐type and transmission‐type metasurfaces. Aiming at maintaining high operating efficiency and in meantime implementing multiple dimensional manipulations of EM waves, the authors present a concise design of radiation‐type metasurfaces, whose distinctive feature stands that each meta‐atom serves not only as geometry phase provider, but as radiator itself so as to spare primary feeds. To further achieve full phase modulation for arbitrary linear polarized radiations and abate innate conjugacy to orthogonal circular polarized radiations, the propagation phase is introduced irrelevant to geometry ones. Based on the radiation‐type metasurface with 0.07‐wavelength low profile, the authors verify experimentally advanced radiation functions for different polarizations like orbital angular momentum beams, asymmetric beams, and time‐reversed focusing. Compared with traditional planar arrays that rely on feeding networks to realize phase modulation, this design provides the possibility to achieve direct phase and polarization modulation at the element level, thus is with less complexity.