A Multiband, Multimode Metasurface With Only Single Port for High-Selective Electromagnetic Energy Harvesting

This paper presents a novel, low-cost metasurface (MS)-based energy harvester for high-selectivity radio-frequency energy harvesting (RFEH). Each cell of the proposed MS integrates four interconnected spoof localized surface plasmon (SLSP) ring resonators in an air-gapped asymmetric topology, using only a single port. A compact, dual-band, low-input-power rectifier is also developed to construct an RFEH microsystem. Main contributions of this paper include: 1) a high-selectivity energy harvesting across multiple wide bands under two controlled linear-polarization (LP) modes, enabling flexible operations in complex RF environments; 2) a single-port-per-cell configuration, reducing the integration complexity; and 3) an SLSP-based folded multilayer structure with a low-cost, air-gapped topology, enhancing both the compactness and affordability. Systematic measurement results on a fabricated 4×4 MS array with the rectifier reveal: 1) high harvesting efficiency and strong selectivity of the MS cell at 1.78–2.40/2.61–2.95 GHz (Mode 1) and 3.49–3.96 GHz (Mode 2); 2) maximum load absorption efficiencies of 81.70% (Mode 1) and 86.33% (Mode 2), with corresponding fractional bandwidths of 49.5% and 12.6%; 3) stable performance of the MS cell under oblique incidence angles of 0°–30°; 4) wireless energy harvesting (WEH) efficiencies of 55.97% (Mode 1) and 65.47% (Mode 2) for the integrated system at an incident power density of 0.87 μW/mm<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup>. The experimental results show good agreements with the simulated ones, validating the feasibility and superior performance of the proposed MS harvester.