Introduction
Passive UHF radio frequency identification (RFID) is now seeing widespread application in a number of areas for identifying and tracking of objects[1]. Tag read range is typically limited by the need to have enough reader signal at the tag to power up the RFID IC. In addition to supplying power to the IC, the reader signal is also modulated with data and commands for the tag. RFID tags, in turn, communicate to the reader by modulating the reader signal and backscattering it to the reader.