An Optimized 2.4 GHz RF Energy Harvester for Energizing Low-Power Wireless Sensor Platforms

摘要

The lifetime of battery-operated sensor platforms (i.e., sensor nodes) is a critical issue. The replacement of their batteries is quite a challenging task if these platforms are deployed for detecting events in inaccessible geographical areas (e.g., forest). This paper describes an optimized RF energy harvester/scavenger (consisting of an antenna, impedance matching circuit and rectifier) for energizing low-power sensor platforms (electronic systems). Few nonmatched rectifiers (using HSMS-285X Schottky diodes) are fabricated to characterize the input impedance for different sets of parameters. After characterization a proper impedance matching circuit is integrated for the maximum power transfer from antenna to rectifier. It is shown that a single stage of RF rectifier is enough to produce output voltage of 1.8 V. Very few realizations of RF energy harvester are reported in the literature under 2.4 GHz ISM band category. Furthermore, high-gain microstrip patch array antennas are fabricated to capture the maximum power from the surroundings. The maximum harvesting range of 0.92 m is obtained at 27 dBm transmitting power level.