Highly efficient dual band 2.45/5.85 GHz rectifier for RF energy harvesting applications in ISM band

A highly efficient single branch dual-band rectifier operating at 2.45GHz and 5.8 GHz for various Radio Frequency (RF) Energy harvesting applications is presented. The circuit consists of a voltage doubler, an impedance matching network, and a load resistor. The diode used for rectification is SMS-7630 by Skyworks and its selection has been justified by a comparative study of diodes. An extremely low loss microstrip line based dual band impedance transformer is used for impedance matching. The circuit has been designed on 1.57mm thick Rogers RT/duriod 5880 substrate because of its low dissipation factor. The power levels of interest are from −10 dBm to −30 dBm. The simulated conversion efficiency of the rectifier is 50.7% at 2.45 GHz and 20.1% at 5.8 GHz for a typical input power of −10 dBm, which are the highest reported efficiencies at this power level at these frequencies. The peak conversion efficiencies for the proposed rectifier are 57.1% for 2.45 GHz and 39.2% for 5.8 GHz. Measurements show good agreement with the simulated results. 21.71 uW DC power is harvested with this rectifier with an overall measured conversion efficiency of 23.26% for an input of −10.3dBm channel power.