Polarization-Insensitive Fractal Metamaterial Surface for Energy Harvesting in IoT Applications

A novel fractal-based metamaterial unit cell, useful for ambient power harvesting, is proposed to operate within the 2.45 GHz Wi-Fi band. The simulated fractal cell offers very high absorption coefficients, a wide-angle and polarization-insensitive behavior, and very small size. A 9 × 9 fractal-based metamaterial harvester is designed and simulated, by demonstrating a very high harvesting efficiency equal to 96.5% at 2.45 GHz. The proposed metamaterial configuration could be very appealing for the implementation of high efficiencies and compact harvesting systems for wireless sensor network applications.