Wide-angle Meta-reflector Using a Non-periodic Metasurface

Metasurfaces have attracted intensive interest due to their strong capabilities in controlling electromagnetic wave, and many efforts have been devoted to realizing wide-angle and wide-band meta-devices. Here, we report a strategy of designing non-periodic meta-reflector in microwave regime, which can possess distinct reflection angles for impinging waves at different incident angle θ
i
. For verification, strict theory is developed to design a non-periodic meta-reflector targeted at f
0
= 15 GHz from the generalized Snell’s law. Our proposed meta-atom is composed of an ultrathin inclined single-layer flexible dielectric board sandwiched between printed circular ring-split resonator and a metallic ground. By optimizing the radius of circular ring-split and β of the 3D meta-atom, we can ensure that reflection phase achieves full 2π coverage and numerical phase difference is less than 20° from the expected one within θ
i
ranging from 0° to 45° in transverse-electric (TE) wave. Therein, linear phase gradient is nearly maintained under different θ
i
. Numerical results show that reflection angle θ
r
varies within 10° ~ 62° by changing θ
i
, which are highly consistent with theoretical prediction. Compared to other wide-angle meta-reflectors, our non-periodic strategy provides a new platform for angle-sensitive meta-devices, which should stimulate many interesting applications in practice.