RFID technology for use in real-time object identification is being rapidly adopted in several fields such as logistic, automotive, surveillance, automation systems, etc. [1]. A radiofrequency identification (RFID) system consists of readers and tags applied to objects. The reader interrogates the tags via a wireless link to obtain the data stored on them. The cheapest RFID tags with the largest commercial potential are passive or semi-passive, and the energy necessary for tag–reader communication is harvested from the reader’s signal. Passive RFID tags are usually based on backscatter modulation, where the antenna reflection properties are changed according to information data [2].