A Highly Efficient Hybrid WPT System Possessing Beam-Steering Beam-Splitting and Near-Field Focusing Capability at ISM Band

Abstract

This article proposes a new hybrid wireless power transfer (WPT) system that can charge: a single target (fixed/moving), multiple targets simultaneously, and a single target quickly. The proposed WPT system can operate either in beam-steering mode for charging a device in motion or in focusing mode for faster charging of a single device. In addition, the beam-splitting capability of the proposed WPT system ensures simultaneous charging of up to four devices. The proposed system utilizes a $2\times 2$ array antenna as its transmitting element and a flexible receiving antenna operating at the industrial, scientific, and medical (ISM) band (2.40–2.50 GHz). An innovative feeding network consisting of active switches, radial stubs, and quarter-wave transformers has been designed. By controlling the biasing of active switches, the beam pattern of transmitting array can be switched between its ten operating states. In seven of its operating states, the transmitting array steers the radiated beam in seven different directions, while in the other three states, it splits the radiated beam into two, three, or four beams. To realize faster charging, a near-field focusing (NFF) metasurface (MTS) has also been designed and integrated to enhance the power transfer efficiency (PTE) to 40.27% over a transfer distance of 50 mm.