Development of wireless energy harvesting circuit using radio waves from a TV broadcasting tower

With the increased growth of IoT devices, the supply of power to low-power devices, such as sensors and communication modules, has become problematic. This study develops a rectifier circuit that generates a large DC output voltage from the received high-frequency signal, targeting the frequency band of 470 to 710 MHz used in terrestrial digital broadcasting towers. The size of our proposed rectifier is 35 × 57 mm. Next, we connect devices, such as a temperature and humidity sensor and Bluetooth low energy module to the developed rectifier circuit, and transmit data without a power supply. We validate a sustained operation of the sensor system at a distance of 7.5 km from a TV broadcasting tower.