Wide-Scanning Reflector-Based Holographic Metasurfaces with Open-Stopband Suppression

In this article, a wide-scanning reflector-based holographic metasurface with open-stopband suppression is proposed for microwave and millimeter-wave applications. By employing a parabolic reflector and using a nonuniform proportional modulation method, the gain bandwidth and aperture efficiency are simultaneously improved. Moreover, anisotropic holographic metasurface is proposed to suppress the open-stopband (OSB) issue. In this case, the reflection coefficient and antenna gain no longer deteriorate rapidly when the beams scan through the broadside, and thus obtaining a wide beam coverage including the elevation angle of zero degree. The measurement results show that the isotropic holographic metasurface achieves a 3-dB gain bandwidth of 39.2% and a maximum aperture efficiency of 30.2%, while the anisotropic design achieves a simulated 3-dB gain bandwidth of 36% and a maximum aperture efficiency of 35.9%. The proposed metasurface features low cost, high gain, wide scanning range, and planar integration, which is a good candidate for multi-point energy transfer or beam scanning applications.