Efficiency Enhancement in Mid-Range RWPT Systems by GRIN Metasurface Lenses

Abstract

The Magnetic Resonant Wireless Power Transfer (RWPT) is one of the best suitable techniques for mid-range applications. Therefore, there are different approaches to enhance RWPT efficiency, many of them based on metamaterial devices. In this work, the GRadient-INdex (GRIN) technique is applied to increase the coupling between transmitter and receiver coils and collimate the magnetic field, reducing its dispersion. This proposed lens topology operates at 28 MHz and is formed by a 5x5 planar and periodic arrangement of Split Ring Resonators (SRR) unit cells. In each one, a lumped capacitor is added to reduce the lens's size and radially create a refractive index gradient. Then, a four-coil RWPT system is designed at the same operating frequency. Finally, the coils and lenses are prototyped, and the RWPT efficiency is measured in three cases: without any lenses, with a conventional (uniform) metasurface, and with the proposed GRIN lens. The experimental results demonstrate that the RWPT efficiency, which is about 8% without any lenses, becomes almost four times higher (33%) after the inclusion of metasurface GRIN lenses. When the same measurement is carried out with a uniform lens, typical topology in literature, the obtained efficiency is 17.59%, nearly half of the obtained with the proposed metasurface.

Artificial Intelligence in Meta-optics

“…In conjunction with the commercial optical simulation tools, CMA-ES can optimize the dimensions of each meta-atom. It was used for the nanostructure optimization of metasurface-enabled waveplates and a gradient-index (GRIN) metasurface lens . CMA-ES also demonstrated topology-optimization capabilities in thermal cloaks .…”

“…It was used for the nanostructure optimization of metasurface-enabled waveplates 176 and a gradient-index (GRIN) metasurface lens. 177 CMA-ES also demonstrated topology-optimization capabilities in thermal cloaks. 178 As a global optimizer, CMA-ES provides designers with the confidence to achieve optimal target performance.…”

Thin-Wire EFIE-MoM Formulation for Fast Computational Analysis of Microstrip Metasurfaces

“…A magnetic MTS lens is used as a case study for validating the proposed numerical formulation. The detailed design procedure, dimensions, and performance of the analyzed uniform lens are described in [9]. As shown in the problem geometry in Fig.…”