A metasurface for conversion of electromagnetic radiation to DC

Abstract

We present a metasurface electromagnetic energy harvester based on electrically small resonators. An array of 8× 8 cross resonators was designed to operate at 3GHz. Unlike earlier designs of metasurface harvesters where each resonator was connected to a single rectifier or load, in this work the received power by all resonators is channeled to a single rectifier which in turn channels the DC energy to a single 50Ω resistive load. The critical advantage of the proposed structure is maximizing power density per diode which maximizes the diode turn-on time. We show through simulation and measurements that the proposed metasurface harvester provides Radiation to DC conversion efficiency of more than 40%.

Low-Cost Air Gap Metasurface Structure for High Absorption Efficiency Energy Harvesting

“…It should be noted that the most part of the available literature only provides results in terms of unit-cell efficiency, without considering harvester practical implementation aspects such as combining network insertion loss and array periodicity interruption. Nonetheless, from Table 3 it can be deduced that the employment of an air gap structure for our design is beneficial to costs and overall efficiency (larger than that of [18] and very similar to that of [19]), even if, in general, the use of a suspended structure might increases thickness and fabrication complexity (since vias have to be connected through air). Nevertheless, the proposed metasurface enhances the wireless power collection with respect to the other referred structures because of a larger collection surface and, consequently, achieves improved overall energy harvesting performance.…”

“…e optimized dimensions of the unit cell are listed in Table 2. e combining network is designed with microstrip technology, where matched T-junctions are implemented with quarter-wave transformers [18], and an SMA connector is soldered at the network output (not present in Figure 5(b)). Simulation results of the combining network are shown in Figure 6.…”

“…Furthermore, unit-cell area is only 0.026λ 2 , which means that the collected power will be very small, making the design of a highly effective AC-to-DC rectifier very challenging. In order to alleviate this problem, an RF collection network is employed with 8 × 8 metasurface arrays, achieving however reduced efficiencies if compared with single unit-cell results, i.e., measured peak efficiencies of 78% [18] and 86% [19], respectively. Another possible strategy to increase the collected power is the design of unit cells with larger area, as it has been presented in [20] by realizing a tightly coupled antenna structure whose unit cells are about five times larger than usually employed metamaterial unit cells.…”

Flexible Manipulation of Emitting Beams Using Single‐Aperture Circularly Polarized Digital Metasurface Antennas: Multi‐Beam Radiation toward Vortex‐Beam Generation

“…[ 38 ] In these architectures, the ensemble of the occupying meta‐atoms is overall seen as the radiator component. Despite all the studies in this field, [ 39–41 ] the room is still free for designing digital true metasurface antennas and gaining more advanced radiation features like multi‐beam emission and circular polarization, which have not been reported, yet.…”

Efficient Metasurface Rectenna for Electromagnetic Wireless Power Transfer and Energy Harvesting

“…Validation is carried out through measuring the collected DC power in an anechoic chamber setting. We emphasize that the energy harvesting system presented in this work is composed of sub-blocks proposed in earlier works for energy absorption and metasurface antennas [7,8]. Figure 1 shows the ELC resonator element (unit cell) used in this work to collect the EM energy.…”