Measurement and analysis of significant effects on charging times of radio frequency energy harvesting systems

Abstract

Radio frequency (RF) energy harvesting as an alternative energy source is an emerging technology that supplies energy for low power wireless devices. In this study, the impacts of RF sources, antenna gains, output power levels and path losses on charging times of an RF energy harvesting system were measured and analyzed in detail. An advanced measurement system that consisted of RF sources used as signal generators, dipole and patch antennas, an RF energy harvesting circuit and the other auxiliary devices were installed for acquiring measurement samples. The generated RF power signals in continuous wave mode at 915 MHz carrier frequency were collected wirelessly by the RF energy harvesting circuit for different antenna gains and output power levels at distances from 20 to 50 cm at the interval of 5 cm. The measurement samples were analyzed statistically. According to the measurement results, it was determined that double RF sources, 6.1 dBi antenna gain and 17 dBm output power level reduced the charging times by 63.09%, 59.24% and 46.41% on average, respectively.