Design of a Novel Passive Radio Frequency Energy Harvesting System

Radio Frequency Identification (RFID) is one of the most exciting technologies that revolutionize wireless communication. RFID can be used in many areas such as environmental monitoring, highway toll collection, industrial control and defense etc. Integrated passive RFID tag is the ultimate solution to minimize the costs and sizes of RFID tags. High gain antenna, high efficiency RF-DC rectifier and low power mixed signal circuitry are the three basic requirements necessary to achieve this above goal. Proposed novel RFID energy harvesting system consists of an antenna, RF-DC rectifier, storage capacitor, voltage sensor and a DC-DC regulator and it operates in very low input power. Designing and implementing a high gain antenna is crucial because the gain of the antenna relates to the generated power for the passive RFID tag. Implementation results of the proposed novel RF- DC rectifier circuit demonstrate a higher DC output voltage than the conventional rectifier circuits. Proposed RF-DC rectifier was designed using low turn on Schottky diodes and high self-inductance frequency capacitors. It was designed using AWR software and fabricated in microstrip technology. It is very crucial that the current dissipation of the whole system to be kept minimum during this time. This system was enabled by the voltage sensor circuit when the voltage stored in the storage capacitor exceeds an upper threshold value. This proposed passive RFID energy harvesting circuit can be fabricated as a compact design with an on chip antenna.