Wireless Sensor and Communication Nodes with Energy Harvesting

Energy is a valuable resource in wireless communication, navigation and sensor nodes. Maintenance and replacement of batteries in battery-driven nodes may not be possible, cost-effective or suitable for many applications. On the other hand, energy harvesting provides sustainable and independent operation with very long life-time but usually with unregulated power flow. The design approaches in present systems based on a regulated flow of power from an energy storage device are not optimal for energy harvesting nodes. This paper briefly reviews the capabilities of the present energy harvesting technologies and some intelligent design approaches based on unregulated supply power to energy harvesting nodes. The paper also presents a brief review of the alternative approaches for in-body communications with energy harvesting. The use of THz band does not seem to be feasible because of the excessive signal attenuation in the in-body channel. However, radio-frequency identification (RFID) with inductive magnetic coupling looks appropriate due to the fact that the human body behaves like free space to the magnetic field but strongly attenuates the electric field.