Conformable dual‐band wireless energy harvester dedicated to the urban environment

This study presents a wireless energy harvester optimized to convert far‐field radio frequency (RF) energy to direct current (DC) voltages at very low received power levels. It is based on a conformable dual‐band rectenna implemented on a polyimide‐based flexible substrate using screen printing technology and commercially off the shelf devices. At 900 MHz, the proposed rectenna provides a rectified voltage of 1 V for a power density of 10.5 mW m −2 and features an RF to DC conversion of 20% for an available input power of −15 dBm reaching 30% at −5 dBm. At 2.4 GHz, the optimal efficiency is only 10%. The harvester has been characterized in laboratory and then tested in a realistic scenario: the remote powering of a clock, consuming 5 μA at 1 V is demonstrated with a smartphone downloading a video at 30 cm.