Metasurfaces have shown great potential in achieving low-cost and low-complexity signal enhancement and redirection. Due to the low transmission power and high attenuation issues of current high-frequency communication technology, it is necessary to explore signal redirection technology based on metasurfaces. This paper presents an innovative metasurface for indoor signal enhancement and redirection, featuring thin thickness, high gain, and wide-angle deflection. The metasurface integrates the design principles of a Fabry-Perot cavity (FPC) theory with a Phase Gradient Partially Reflective Metasurface (PGPRM). Its unit is a fishnet structure with a substrate only 1/33 λ thin. Based on the precise phase control of the dual-layer PGPRM (with an inter-layer distance of 8 mm), the proposed metasurface can obtain phase coverage as small as 78° while achieving high-gain beam deflection as large as 47°. Simulation results show that within the band 8.6-9.2 GHz (6.7%), a single-layer metasurface can deflect the beam to 29° with a maximum gain of 16.9 dBi. In addition, it is also 360° polarization-insensitive in the xoy plane at 9 GHz with large-angle deflection characteristic retained. Moreover, cascading PGPRM can effectively improve the beam deflection angle. After analysis, the scheme with a double-layer spacing of 8 mm was ultimately selected. Simulation results show a double-layer metasurface can deflect the beam to 47° with a maximum gain of 16.4 dBi. This design provides an efficient and cost-effective solution for large-angle beam deflection with gain enhancement for indoor wireless communication.
Keywords: Fabry–Perot cavity (FPC) theory; Phase Gradient Partially Reflective Metasurface (PGPRM); high gain; large-angle beam deflection; metasurface; polarization insensitive.