Dual-Band Rectenna for Wireless Power Transfer Applications

Abstract

This thesis presents a Dual-Band Rectenna which is designed to harvest Wireless Power from the ambient environment and its conversion to DC voltage. It is designed to harvest power from the widely used UHF 900 MHz and the 2.45 GHz Industrial, Scientific and Medical (ISM) Radio Bands, and is targeted towards Radio Frequency Identification (RFID) and Wireless Sensor Systems. The Bandwidth of the Rectenna has been chosen to operate in the widely used 900 MHz UHF RFID bands of Europe, United States and China to make it suitable for RFID WPT systems worldwide. The Rectenna is realized by designing a Dual-Band Antenna and a Dual-Band Rectifier. The Microstrip Multi-Resonant Antenna which operated in the desired Frequency Bands is designed which used multiple Radiating and Shorted Strips and a Lumped Element Matching Network to cover both Frequency Bands with the intended Bandwidth. The Microstrip Dual Band Rectifier is designed by implementing a Power Divider to separate the UHF and ISM Frequency signals into individual branches. The separated UHF and ISM signals are subsequently rectified using Diode Rectifiers in the Voltage-Doubler Configuration. Impedance Matching Networks are designed to match the Diode Rectifiers to the Line Impedance of 50Ω. The compact nature of the Dual-Band Rectenna, with the overall size of 45×80 mm2 makes it possible for it to fit on a Standard RFID Card. Its Wide Spectrum of Operation, good Wireless to DC Conversion Efficiency make it a suitable potential candidate for RFID and general Wireless Power Transfer and Harvesting Systems