Energy Harvesting from Ambient Radiation Sources for Ultralow Power Devices

Energy harvesting from ambient radiation (non-optical radiation) has the potential to extend the useful life of low-power electronic devices and sensors by recharging its battery. Ambient radiation sources include power lines, radio waves, microwaves, mobile networks, and Wi-Fi signals. According to Faraday’s law, an alternating electromagnetic field can be used to induce an alternating electrical current (AC) in a nearby conductor. The alternating current can then be converted to a direct current (DC) and used to recharge the battery. In this work, we present an ambient radiation energy harvesting circuit capable of acting as a DC power source. We first present our basic inductor-rectifier circuit, its efficiency, and its output performance for various input voltages and frequencies. We then demonstrate how the basic inductor circuit can be combined with a ten-stage Cockcroft-Walton voltage multiplier circuit to boost the DC voltage to any battery level. The authors also show that multiple inductors can be wired together in a specific manner to multiply the output alternating current across a broad frequency range with high efficiency. Similarly, we show how multiple inductors can be wired together to linearly boost the output AC voltage, also across a broad frequency range and with high efficiency. These various setups demonstrate that one can effectively take low-power input signals and boost the output power using only passive components.