CHAPTER 9
OPTICAL BEAMFORMING PHASED ARRAYS FOR UWB CHIPLESS RFID READER
9.1 INTRODUCTION
The current market volume of the RFID industry is worth approximately $5.25 billion in 2009. The industry will grow exponentially with the invention of a very low cost tag, with unit cost in the range of less than a cent. RFID technology can be classified into: (i) systems where the tag contains a microcontroller and (ii) systems where the transponder is “chipless.” Das and Harrop [1] argue that the largest market in RFID lies with the chipless RFID as opposed to any type of chipped RFID. The cost of chipless tags is generally much lower than that of other tag types due to the absence of the microcontroller. To make significant market impact, chipless RFID systems need to have reasonable read range (>30 cm), with tags that are small in size, flexible, and printable for low cost to compete with the optical barcode. With the exception of surface acoustic wave (SAW)-based RFID [2], no other chipless technology has made a significant impact on the market. However, SAW tags are rigid and bulky, making them unsuitable for some applications. There are a few printable chipless tags reported in the open literature [3–9]. They are printed stripline ...
