Integrating magnetic resonance coupling with radio frequency energy to wirelessly charge mobile device batteries

Abstract

Mobile devices are rapidly evolving, with new features being continuously integrated into smartphones and an increasing number of apps being developed to enhance user convenience. The convenience of these mobile devices is constrained only by the lifespan of their batteries. The reliance on mobile devices like smartphones necessitates frequent battery charging, which can be inconvenient for users since the device becomes unusable during charging. Additionally, unnecessary charging leads to wasted electricity, a significant concern given the ongoing electricity crisis. Wireless Power Transfer (WPT) offers an efficient solution for charging mobile device batteries without the need for wires. This research aimed to present the results of a WPT prototype circuit that combines magnetic resonance coupling with harvested Radio Frequency (RF) energy to enable wireless power transmission for recharging mobile devices. Initial work on the RF energy harvesting circuit has been conducted, yielding promising results. WPT enables the transmission of energy or power from a transmitting component to a receiving component through a pulsating magnetic field. This process enables electricity to travel wirelessly from a power source, such as harvested RF energy, to an electrical load, like a mobile device battery, without the need for physical connectors, bridging the gap through non-contact transmission. A wireless power system fundamentally relies on a pair of coils: one for transmitting energy and the other for receiving it. The transmitting coil is energized by an alternating current (AC), generating a magnetic field that induces a current in the receiving coil. Harvested RF energy is converted into high-frequency AC through precisely designed electronics embedded within the transmitter. The AC is supplied to a copper wire coil in the transmitter, generating a magnetic field. When the receiving coil is placed near the magnetic field, it induces an alternating current (AC) within the coil. The integrated electronic components in the receiving device then convert the AC into direct current (DC), delivering useful power. The experimental design of the WPT charging circuit, incorporating an RF harvesting circuit and magnetic resonance coupling, has shown promising performance. A mathematical modelling and simulation research approach was employed to integrate magnetic resonance coupling with harvested RF energy in the wireless charging system. The developed model included constructing a WPT charging circuit prototype that incorporated RF-harvested energy and magnetic resonance coupling (magnetic coils). The LTSpice simulation software was utilised to evaluate the feasibility of integrating capacitors into the circuit layout. The study's findings validate the successful development of a WPT charging circuit capable of wirelessly charging a mobile device battery. Furthermore, the research explores an alternative energy storage solution by substituting a capacitor for the mobile device battery.