Quantized Bessel Phase and Embedded Gaussian Tapering for Near-Field Wireless Power Transfer Using Low-Cost Metasurface Lenses

This paper presents the experimental demonstration of a low-cost metasurface lens for near-field wireless power transfer (WPT) at 24 GHz. The lens is horn-fed and engineered to embed quantized spherical-phase control and Gaussian amplitude tapering directly into its physical structure. Both functionalities are realized through geometric variation in cross-shaped unit cells distributed across a 10λ × 10λ aperture. This dual-control strategy enhances near-field focusing by mitigating quantization artifacts and edge diffraction effects. Fabricated using standard PCB processes, the metasurface achieves efficient energy convergence without auxiliary feed shaping. Measurement results confirm a tightly confined beam sustained over a 7.6λ depth and a 5.8 dB enhancement in transmission coefficient$\vert S_{21}\vert$relative to free-space propagation. These findings validate the effectiveness of geometry-driven amplitude tapering in improving spatial energy localization for compact WPT systems.