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

Abstract

is manuscript deals with the design of a metamaterial-based surface structure for high efficiency wireless power harvesting or collection. Differently from the previously presented structures which require the use of thicker and low-loss (and for this reason high cost) dielectric substrates, the presented work employs a dual-layer structure with a thin low-loss material and an air gap; they allow for the design of very high absorption efficiency metamaterial-based surfaces, with noticeably reduced costs. Furthermore, the air gap thickness can be used as a new degree-of-freedom (more easily adjustable than the thickness of a single-layer structure) for the optimization of other design requirements such as bandwidth or structure sizes. In comparison with other existing designs, the proposed metasurface shows a comparable absorption efficiency of 84.4% but with a larger power collection surface and lower costs.

A Review of Metasurfaces for Microwave Energy Transmission and Harvesting in Wireless Powered Networks

“…The energy conversion efficiencies realized in [80], [82]- [84], [87]- [91] established the viability of 2D arrays of microwave energy harvesting meta-cells. These implementations can serve as energy collectors in receivers for microwave energy transmission links served by a dedicated wireless source, especially within the radiative near-field.…”

“…While it is typical for metasurface harvesters to consist of dielectric substrates sandwiched between two conducting surfaces, [90], [91] realize the harvester as a dual-layer structure of thin low-loss surfaces separated by an air gap, as illustrated in Fig. 8a.…”

Microwave Metamaterial Absorber with Radio Frequency/Direct Current Converter for Electromagnetic Harvesting System

“…Their undeniable advantages, including low production costs, simple construction, and the availability of materials used in their manufacturing, make them attractive structures for research, with potential practical implementation. Although some MM structures exhibit a high absorption efficiency with regard to EM radiation (of the order of 80% [10][11][12][13]), new MM structures are under study [10][11][12][13]. Another challenge MM harvesting technology faces is an unsatisfactory efficiency in converting the absorbed EM energy by MM structures into electrical energy by RF/DC converters (less than 50% [14][15][16]).…”

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

“…To this end, metasurface (or metamaterial) structures have been recently proposed as a promising alternative to conventional rectennas, with the key advantage of greater amounts of harvested power and higher efficiencies in the preliminary conversion stage from RF-to-AC power [13][14][15][16][17][18][19][20][21]. A metamaterial harvester comprises an array of electrically small resonators, printed on a grounded dielectric substrate.…”

“…A metamaterial device, consisting of four identical omega ring resonators arranged in rotational symmetry, is proposed in [19] to operate at 5.8 GHz, offering an efficiency up to 93.1%, under normal incidence. A low-cost air gap metasurface structure is illustrated and discussed in [20] to resonate around 2.45 GHz with an RF-to-AC efficiency of about 85.9%.…”