High-efficiency wideband flat focusing reflector mediated by metasurfaces

We propose to achieve a high-efficiency wideband flat focusing reflector using metasurfaces. To obtain the wide band, the polarization conversion mechanism is introduced into the reflector design, based on the fact that the reflection phases of cross-polarized waves are linear in quite a wide band. This facilitates the design of wideband parabolic reflection phase profile. As an example, we design two reflective focusing metasurfaces with one- and two-dimensional in-plane parabolic reflection phase profiles based on elliptical split ring resonators (ESRRs). Both the simulation and experiment verify the wideband focusing performance in 10.0-22.0 GHz of the flat reflectors. Due to the wide operating band, such reflectors have important application values in communication, detection, measurement, imaging, etc.