In this paper, based on rotation phase-gradient principle, a single-layer, high-efficiency transmitting metasurface is designed and applied to high-gain antenna. In the case of circularly polarized incident wave, the PCR (polarization conversions ratio) of the metasurface element is greater than 90% in the band of 9.11-10.48 GHz. The transmitting wave emerges an anomalous refraction when left-handed circularly polarized wave are incident perpendicularly to the 1D phase-gradient metasurface, which is composed of cycle arrangement of 6 units with step value of 30°. The simulated anomalous refraction angle is 40.1°, coincided with the theoretical design value (40.6°). For further application, the 2D focused metasurface is designed to enhance the antenna performance while the left-handed circularly polarized antenna is placed at the focus. The simulated max gain is increased by 12 dB (182%) and the half-power beamwidth is reduced by 74.6°. The measured results are coincided with the simulations, which indicates the antenna has high directivity. The designed single-layer transmission metasurface has advantages of thin thickness (only 1.5 mm), high efficiency and light weight, and will have important application prospects in polarization conversion and beam control.

We propose a design of high-efficiency and direction-controllable spoof surface plasmon polaritons (SSPPs) coupler based on a Pancharatnam–Berry (PB) metasurface and a diode-controlled, linear-to-circular polarization conversion metasurface (PCM). The PB metasurface was designed to achieve high-efficiency excitation of SSPPs by manipulating the phase distribution. The PCM was placed above the PB metasurface at a certain distance, and the propagation direction of SSPPs could be controlled by changing the bias voltage of PCM. To validate the feasibility of the proposed design, a SSPPs coupler was fabricated and assessed. The experimental results were in good agreement with the simulation results. The conversion efficiency from the free space wave to SSPPs was obtained to be as high as 0.76 at 10 GHz, and the propagation direction of SSPPs became controllable under the normal incidence of x-polarized waves on the PCM. Compared to conventional devices such as prism, grating, and gradient-index metasurfaces, the proposed SSPPs coupler is more suitable for SSPPs excitation, thereby providing an interesting route toward developing plasmonic devices.

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