Multi-band simultaneous radio frequency energy harvesting

This paper presents a multi-band simultaneous RF energy harvesting system. The input impedance and the output voltage of a voltage multiplier are investigated. The maximum number of cascaded rectifying stages are identified for three different operating frequencies, 900 MHz, 1800 MHz and 2.45 GHz. The harvesting system combines the DC output voltage of three single-frequency RF harvesters. The combined system allows an efficiency increase by 15 % compared to the efficiency of each sub-system. At an input power level of -15 dBm, the system efficiency reaches 45 % at 900 MHz, 46 % at 1800 MHz and 25 % at 2.45 GHz. Compared to the state-of-the-art, the suggested system has the ability to harvest RF power at different operating frequencies.