146 Copyright © 2012, IGI Global. Copying or distributing in print or electronic forms without written permission of IGI Global is prohibited. Chapter 8 1. INTRODUCTION The history of Radio Frequency IDentification (RFID), birth and development, are described in several relevant publications (Landt, 2001; Finkenzeller, 2004). The principle of RFID communication was clearly explained in an IRE publication by H. Stockman in 1948 (Stockman, 1948). Even if it is generally said that the first application of RFID is the Identify Friend or Foe (IFF) system introduced by Watson-Watt, the first real device that we can consider as the ancestor of modern tags is the “thing” designed by Leon Theremin (Glinsky, 2005). The later is Smail Tedjini Grenoble-INP/LCIS, France Etienne Perret Grenoble-INP/LCIS, France Arnaud Vena Grenoble-INP/LCIS, France Darine Kaddour Grenoble-INP/LCIS, France Mastering the Electromagnetic Signature of Chipless RFID Tags ABSTRACT The rapid development in wireless identification devices and subsequent applications is at the origin of intensive investigations in order to fulfill various constraints that can exist when implementing ap- plications in practice. Chipless technologies have many advantages. They are fundamentally wireless and powerless devices, and can be all passive components, which potentially means infinite lifetime. However, chipless technology is still in its infancy age, even if it is the most effective for cost reduction. One of the most important features of chipless is coding capacity and ways to imprint it into the device. This chapter will review and discuss various coding techniques. It will address a comparison of the most relevant coding techniques. For sake of clarity some global parameters that can be used as figure of merit will be introduced and applied to compare different practical chipless tags. DOI: 10.4018/978-1-4666-1616-5.ch008