A novel human body channel (HBC) energy harvesting scheme for body sensor networks (BSNs) is proposed in this paper. Human body channel is utilized innovatively as energy transmission medium to reduce the transmission loss dramatically and eliminate influence of shadow effect. Further, a high sensitivity and efficiency rectifier is presented by introducing an effective threshold compensation circuit.
Experimental results of the energy harvesting scheme show that it can supply 2-μW power typically at −5 dBm transmitted power and up to 19.5-μW at +7 dBm transmitted power by 30 cm distance of human body channel. The sensitivity of the proposed rectifier is −22.5 dBm with 1-V output voltage. When offering 5-μA output current, the rectifier can achieve 25.87% efficiency. The rectifier is implemented in a standard 0.18-μm CMOS process and operating frequency is 145 MHz.