Polarization-insensitive microwave power receiving composite array based on reflection phase gradient metasurfaces

This paper presents a polarization-insensitive microwave power receiving composite metasurface array. The composite array consists of a reflection phase gradient metasurface array and a horizontal omnidirectional antenna, with a central operating frequency of 5.8 GHz. The reflection phase gradient metasurface array elements are insensitive to the polarization of the incident wave and are arranged radially around the array center. This configuration creates a radial reflection phase gradient that efficiently converts incident plane waves of different polarizations into surface waves converging toward the center. The surface wave energy is then extracted by the horizontal omnidirectional antenna and converted into direct current (DC) by a rectifier. Numerical simulations demonstrate that the composite array maintains effective surface wave excitation and propagation toward the center for both circularly polarized and various horizontally polarized plane waves, achieving a plane wave-to-surface wave conversion efficiency of 74.89%. Experimental validation shows that the proposed array achieves a maximum energy collection efficiency of 62.23% and an RF-DC conversion efficiency of 39.96% over a broad frequency range of 5.6–6.0 GHz. This study achieves polarization insensitivity while simultaneously enhancing the operational efficiency of microwave energy receivers. The results offer a valuable design reference for leveraging reflection phase gradient arrays in wireless power transfer applications.