NK2023, Oslo, Norway
Sept 26 - Sept 29, 2023 (Tue. - Fri.), Scandic Holmenkollen Park Hotel
Energy Focusing Single-Layer Metasurface
for Powering Small Unmanned Vehicles
Wonwoo Lee, and Hojin Lee
Abstract
Metasurfaces, that is artificially engineered two-dimensional planar metamaterials, are attracting significant consideration to achieve various functionalities including negative refractive index, anomalous refraction, and planar lenses owing to their capability in manipulating the phase, amplitude, and polarization of electromagnetic waves. In particular, due to their low profile and ease of fabrication characteristics, metasurface lenses that convert an incident plane wavefront into a spherical wavefront could be respectable candidate to solve the problem of power reception and efficiency degradation by focusing the spreading electromagnetic waves, and have become indispensable elements for planar optical devices, compared to conventional optical devices generally rely on gradual phase accumulation in bulk materials. Especially, phase gradient metasurfaces have been highlighted as a promising candidate for realizing electromagnetic-wave-focusing characteristics by manipulating the wavefront through controlling the spatial phase and transmission profiles of metasurfaces. Herein, we propose a single-layer phase-gradient metasurface lens that is capable of effectively controlling the spatial phase and transmission distribution with low-Q resonance properties, as well as with incident angle independency over a wide operating frequency band. From the experimental results, we confirm that the proposed metasurface exhibits electromagnetic-wave-focusing characteristics at 22.5 GHz and maintains a spatially fixed focal point at 13 mm for incident angles from − 30° to 30°. Further, to validate the metasurface based energy-harvesting applications, a low-power and scaled-down small unmanned vehicle powering experiment is performed with an ionic polymer actuator. Based on the energy-harvesting capability of the proposed metasurface for powering small unmanned devices, we could demonstrate the low power unmanned "bug", and the unmanned actuator moved forward about 26 mm in 25 seconds validating the feasibility of the proposed WPT system for powering small unmanned devices, which can be potentially extended to full-scale, high power, longer range operation.
