Highly Efficient Polarization-Insensitive Wide-Angle Orthogonal Dipole Metasurface for Ambient Energy Harvesting

Area of Science:

• Electromagnetics and Metamaterials
• Energy Harvesting
• Antenna Theory

Background:

• Ambient radio frequency (RF) energy harvesting is crucial for powering low-power electronic devices.
• Existing solutions often suffer from polarization sensitivity and complex matching networks, limiting efficiency.
• Metasurfaces offer a promising platform for novel antenna and energy harvesting designs.

Purpose of the Study:

• To propose a polarization-insensitive, scalable metasurface array for efficient ambient RF energy harvesting.
• To design a direct-impedance-matching strategy to minimize energy conversion losses.
• To demonstrate high RF-to-DC conversion efficiency across a wide range of incident power levels.

Main Methods:

• Design of an asymmetric planar orthogonal dipole-based metasurface with monolithic Schottky diodes.
• Implementation of a coplanar architecture with integrated inductors for DC channels and RF suppression.
• Fabrication and testing of a 5 × 5 metasurface array prototype at 5.8 GHz.

Main Results:

• Achieved 99% radiation-to-AC efficiency across all polarization angles.
• Demonstrated a peak RF-to-DC conversion efficiency of 77.9% at 25 dBm incident power.
• Exhibited efficiencies exceeding 40% and 60% at 15 dBm and 20 dBm, respectively, showing broad power range capability.

Conclusions:

• The proposed metasurface array offers a scalable, drill-free, and polarization-insensitive solution for ambient RF energy harvesting.
• The direct-impedance-matching strategy significantly enhances energy conversion efficiency.
• The design shows strong potential for practical applications in multipath environments.