Performance Analysis of a Wireless Power Transfer System Employing the Joint MHN-IRS Technology
Electronics 2025
Romāns Kušņins, Kristaps Gailis, Jānis Eidaks, Deniss Kolosovs, Ruslans Babajans, Darja Čirjuļina, Dmitrijs Pikuļins

The present study is concerned with the power transfer efficiency enhancement using a combination of the multi-hop node (MHN) and the Intelligent Reflecting Surface (IRS)-based passive beamforming technologies. The primary objective is to ensure a high RF-DC converter power conversion efficiency (PCE) used at the receiving end, which is difficult to achieve due to path loss and multi-path propagation. An electronically tunable reconfigurable reflectarray (RRA) designed to operate at the sub-GHz ISM band (865.5 MHz) is utilized to implement the IRS concept. Both the MHN and RRA were developed and studied in our earlier research. The RRA redirects the reflected power-carrying wave amplified by the MHN toward the intended receiver. It comprises two layers: the RF layer containing tunable phase shifters and the ground plane. Each phase shifter comprises two identical eight-shaped metal patches coupled by a pair of varactor diodes used to achieve the reflection phase tuning. The phase gradient method is used to synthesize the RRA phase profiles, ensuring different desired reflection angles. The RRA prototype, composed of 36 phase shifters, is employed in conjunction with the MHN equipped with two antennas and an amplifier. The RRA parameter optimization is accomplished by randomly varying the varactor diode voltages and measuring the corresponding received power levels until the power reflected in the desired direction is maximized. Two measurement scenarios are examined: power transmission without and with the MHN. In the first scenario, the received power is calculated and measured at several distinct beam steering angles for different distances between the Tx antenna and RRA. The same procedure is applied to different distances between the RRA and MHN in the second scenario. The effect of slight deviations in the operating frequency from the designed one (865.5 MHz) on the RRA performance is also examined. Additionally, the received power levels for both scenarios are estimated via full-wave analysis performed using the full-wave simulation software Ansys HFSS 2023 R1. A Huygens’ surface equivalence principle-based model decomposition method was developed and employed to reduce the CPU time. The calculated results are consistent with the measured ones. However, some discrepancies attributed to the adverse effect of RRA diode biasing lines, manufacturing tolerances, and imperfection of the indoor environment model are observed.


Keywords
compact reflectarray; wireless power transfer; sub-gigahertz band; double layered reflector
DOI
10.3390/electronics14030636
Hyperlink
https://www.mdpi.com/2079-9292/14/3/636

Kušņins, R., Gailis, K., Eidaks, J., Kolosovs, D., Babajans, R., Čirjuļina, D., Pikuļins, D. Performance Analysis of a Wireless Power Transfer System Employing the Joint MHN-IRS Technology. Electronics, 2025, Vol. 14, No. 3, Article number 636. e-ISSN 2079-9292. Pieejams: doi:10.3390/electronics14030636

Publication language
English (en)
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