Ambient RF energy harvesting from DTV stations

In the framework of wireless power transmission and RF energy harvesting, the main objective is to design a harvester that collects ambient Radio Frequencies (RF) broadcasted from DTV (Digital TV) stations. This paper summarizes the main challenges experienced, when designing such a harvester. The distance and the free space path loss between the transmitting station and the harvesting location are calculated. Using Friis equation, the available power at the harvesting location is predicted. A novel broad-band Yagi-Uda antenna that covers the DTV broadcasting frequencies (470 MHz-810 MHz) is presented. The antenna design is based on integrating a wide-band strip dipole into a Yagi-Uda antenna. Moreover, The rectifier part, which converts the harvested RF power into DC is discussed, the simulated and measured input impedance and the output voltage of different commercial rectifiers are shown. A voltage multiplier is used to maximize the output voltage, and a matching network is presented to match the impedance of the multiplier to that of the antenna.