RF Energy Harvesting for Portable Biomedical Devices

This paper presents the design, simulation and fabrication of a radio frequency (RF) energy harvester for the charging of low power portable biomedical devices. A receiver single patch antenna is modeled, simulated and fabricated which operates in industrial scientific and medical (ISM) band. Moreover, a two stage rectifying and voltage doubler circuit is designed and fabricated which rectified the harvested voltage signal into DC voltage. Furthermore, a matching circuit is also produced for the purpose of delivering higher power to the rectifying circuit. The simulation of receiver antenna has been done with computer simulation technology (CST) software while rectifying circuit has been simulated with an advance design system (ADS) software. A DC voltage of 5.3 V is achieved in simulation which is enough to operate low power biomedical devices. Moreover, the efficiency of different rectifying circuits has been studied and it is found that at 0 dBm the rectifier circuit gives the maximum efficiency of 64%.