Maxime Bernier, Frederic Garet, Etienne Perret, Lionel Duvillaret, and Smail Tedjini
In this article, we present a new family of chipless tags, which permit encoding of digital data in the terahertz domain. These devices consist of stacked dielectric media whose thicknesses are of the same order as terahertz wavelengths. Since the information is encoded in the volume of these multilayer terahertz tags, they can easily be associated with classical identification techniques (e.g., barcode, radio frequency identification), where information is encoded at the surface of the tag, to provide higher data security. The principle of this encoding approach is studied and experimentally demonstrated in this paper. A 2 bit tag prototype has been realized and measured for validation purposes.
Identification and recognition are some of the main topics of great interest in modern societies. Many techniques have been developed in the last century. The most popular are the barcode [1,2] and radio frequency identification (RFID) . Both are based on the use of electromagnetic waves and wireless communication by means of reflected waves. Even though barcodes have the advantage of being low cost, their use is only possible under line of sight conditions, which is a major drawback compared to RFID. Nevertheless, despite of its advantages, the diffusion of the RFID system is slowed down by the tags themselves, which consist of antennas associated with microchips. It is mainly those microchips that involve several economical, technological, or social fences. Among these, the cost of the tags remains too high, and their recycling (tags are made of metals and semiconductors) remains a problem as their production could reach trillions of units per year . Moreover, both of these widely used systems are visibly implemented or attached on the surface of the item one wants to identify, making them subjected to alteration, damage, and illegal copying…
APPLIED OPTICS / Vol. 50, No. 23 / 10 August 2011