Using Metamaterial-Based Coplanar Waveguide Structures for the Design of Antennas on Passive UHF RFID Tags

Radio Frequency Identification (RFID) is becoming a very affordable and reliable way of to track inventory items. Because of this, RFID systems have received considerable attention from researchers, engineers and industry personnel. Particularly, researchers involved with RFID systems have developed smaller antennas for tags deployed in these systems. Several of these designs have involved meander-line antennas (Finkenzeller, 2003), metamaterialbased designs (Dacuna & Pous, 2007) and various materials (Griffin et. al., 2006). This chapter will describe the main parameters of interest in a RFID system using Friis’s transmission equation. This will then be followed by a section on recent work on applying RFID systems to smart shelves, metallic plates and livestock tracking. Then a section on coplanar-waveguides (CPW) is presented followed by the design of metamaterial-based CPW antennas for passive UHF RFID tags.