Efficient conversion of near-field spherical waves to surface waves for microwave energy harvesting

Abstract

Efficient near-field microwave power reception is fundamentally challenged by the spherical nature of incident wavefronts. We address this limitation by demonstrating a receiver based on an explicit analytical phase compensation model. This model enables a phase gradient metasurface to correct near-field phase variations, efficiently converting incident electromagnetic waves into guided surface waves. A composite structure is constructed by integrating a surface-wave parabolic reflector with an omnidirectional antenna to facilitate high-efficiency energy capture. At 5.8 GHz, the device achieves a simulated efficiency of 70.44% and a measured peak efficiency of 60.4%, exhibiting robust performance across the 5.6–6.0 GHz range. This work provides a generalizable design framework, analytically linking near-field wavefront correction to surface-wave engineering, for a class of high-efficiency microwave energy receivers.