Investigating energy harvesting technology to wirelessly change batteries of mobile devices

Abstract

Mobile devices have recently become powerful computing tools for aiding daily tasks. However, their batteries discharge quickly, even if they are not being used mainly because of the heavy computation tasks required by the multimedia applications that run on them. The swift turnover time on the battery life span is challenging as frequent charging is required to keep the device functioning. This is a major bottleneck because of the current energy optimisation crisis, user inconvenience due to constant charging of a battery and erratic nature of the electricity supply in some areas. In the current research project, the primary aim was to explore the energy harvesting technology innovation of radio frequency to wirelessly recharge the batteries of mobile devices. This implied an alternative way of charging the batteries of mobile devices without the need for a physical charger to connect to an electrical outlet. Energy harvesting, which involves making use of free energy from the atmosphere is the most innovative energy efficient wireless charging technology because mobile devices are constantly transmitting radio signals. Radio signals are initially received from the atmosphere through an antenna. Thereafter, these signals are converted using a rectifier circuit, from alternating current into direct current which is then utilised to recharge the battery of a mobile device. This research study adopted a mathematical modelling and simulation research methods. The model involved building an RF energy harvesting prototype. This prototype model displayed the limitations to be considered. The LTSpice simulation software was used to test the feasibility of combining diodes, capacitors and antenna type based on the limitations of the prototype model. The result of this research project demonstrates the building of a radio frequency harvesting circuit that can store a minimum load of 5mV that is required to charge the battery of a mobile device. Moreover, it has explained an alternative storage of the acquired energy using a supercapacitor compared to a mobile device battery.