A Universal Energy Harvesting Scheme for Operating Low-Power Wireless Sensor Nodes Using Multiple Energy Resources

Low-power wireless and sensor technologies are fast proliferating everyday life. Medical and structural implants are common examples of devices based on these technologies. A new term “Internet of Things” has been coined to encompass many such sensors and wireless nodes. One of the critical concerns for their deployment is the source of energy, especially in operational scenarios where wall power is not available. Batteries run out of energy in due course. Solar or other alternatives are not always dependable. Combining various means of energy harvesting schemes assumes significance in this context. Low energy density radiations such as ambient RF signals from various broadcast and cellular towers have been found to be a convenient and widespread source of energy. Incorporating RF harvesting circuits into such a universal energy harvesting platform also enables intentional wireless power transfer to energize the device using an RF transmitter. This chapter explains electronic circuits required for a universal energy harvesting platform to capture, store, and efficiently utilize RF energy at different power levels in combination with other sources of ambient energy such as the Solar (for high energy). For demonstration, a low power radio and the required power management circuit have been integrated with this platform.