A wireless power beaming system using Y shaped reflectarray and rectenna achieving 8.33% power transfer efficiency

In this paper, the design and implementation of a wireless power transfer system using an ultrawideband (UWB) circularly polarized multilayer reflectarray antenna (RA) is proposed. This novel system is the first of its kind to be demonstrated in a distributed transmitter (TX) configuration, presenting enhanced efficiency and versatility. The RA is comprised of novel unit cells of "Y" shape, where a smaller arm is connected with a vertical arm at a 45° tilted angle, and a rectangular shape is incorporated in the middle layer that contributes to enhancing the gain over the frequency band. The proposed RA operates in the ultra-wideband (UWB) frequency bands (5 to 10 GHz), and it uses a horn antenna as a feed. The Y-shaped UWB featured non-uniform element spacing over the active area and a rectangle-shaped middle layer, achieving the realized gain and aperture efficiency enhancement. The antenna achieved a peak realized gain of 21.261 dBi with a 3 dB gain bandwidth (BW) of 18.2%, and a 3 dB axial ratio (AR) BW of 63.11% for transmit antenna (TA) operation. In the proposed distributed WPT system, the spacing between several TXs is optimized in such a way that they are able to generate a collimated beam simultaneously. The achieved Power Transfer Efficiency for different distributed WPT configurations involving one, two, and three transmitters with a single receiver system is 5.03%, 8.33%, and 8.11%, respectively, at a distance of 1.7 m with an antenna spacing of 660 mm. The proposed well-performed WPT system is a promising candidate for long-distance power beaming.