CHAPTER 8
FPGA-CONTROLLED PHASED ARRAY ANTENNA DEVELOPMENT FOR UHF RFID READER
8.1 INTRODUCTION
Radio-frequency identification (RFID) has been classified based on its frequency designations: low-frequency (LF), high-frequency (HF), ultra-high-frequency (UHF), and microwave frequency (MW) tags. Traditionally, LF and HF tags dominated approximated 90% of the RFID tag and reader market due to their mass deployment as animal tags and item tagging [1]. However, after the mandates of using UHF RFID by the biggest retail chain Wal-Mart, UHF RFID has gotten new momentum [2]. The motto is to comply with the UHF regulation by thousands of vendors to tag their manufactured goods and items. The US Department of Defense (DoD) has mandated UHF tags for their operations. UHF RFID system has many advantages over the other types. They are as follows [3]:
1. UHF tags have a maximum reading distance of up to 20 m.
2. Contrary to the microwave tags, UHF tags have the advantage of non-line-of-sight reading capability and little attenuation by the contents and features of items, therefore, reading of UF tags is not blocked by human presence (not attached to body), water, and so on.
3. It has already Gen1 and Gen 2 tags and is universally used in various parts of the world under the mandates of EPC Global, GATG, and CEPT.
4. Contrary ...
