Ambient energy harvesting from two-way talk radio for on-body autonomous wireless sensing network using inkjet and 3D printing

A novel wearable and flexible energy harvesting circuit from a hand-held two-way radio for an energy autonomous on-body sensing network is proposed. The proposed circuit is more efficient than conventional ambient RF energy harvesting architectures because both the dc and the harmonics generated by the rectifier is simultaneously utilized to serve two different functions. The dc power is used to drive dc loads and the harmonic is used to build a carrier emitter for backscatter RFID tags for on-body sensing. The 3D printed substrate is used to alleviate the limitations imposed by the substrate. Both the energy harvester and the custom backscatter RFID tags are fabricated and characterized. The measured dc and the second harmonic, 928 MHz, output power from the proposed rectifier are 17.5 dBm and 1.43 dBm while a two-way talk radio is 9 cm away. The reading range of the custom tag is extended to 17 m with the help of the proposed energy harvester.