Realization of efficient RF energy harvesting circuits employing different matching technique

Abstract

Power management and charging of batteries for wireless sensors become a problem when using them in the field applications. In this paper, we present RF energy harvesting circuit with three different approaches: resonator, number of multiplier stages and low pass filter (LPF). Resonator provide 30 times improvement in amplitude of input (100 mV) AC signal. In proposed circuit L type network, between input power source and rectifier, works as resonator as well as matching network at resonant frequency. It results in maximum efficiency 79% with 50kO load at -10 dBm input power. We also present the effect of multiplier stages on output voltage and RF to DC conversion efficiency. Optimum efficiency of approximately 80% is achieved with Dickson topology in input power region 0 to 10dBm for 3rd, 5th and 7th stages, respectively. Application of LPF is also introduced with an existing circuit. It provides 140 mV improvement in output voltage with input power -10dBm. It also shows that maximum efficiency 75% and 64% is possible with dielectric constant (er=9) and substrate height (H=0.0004m), for microstrip line of matching circuit at -10 dBm input power with 10 kO load.