Toward EPC global chipless RFID tag design

Radio Frequency IDentification (RFID) is a disruptive technology that has penetrated almost every facade of modern civilization. RFID is an automated identification system that uses radio frequency waves to transmit data between a tag and a reader. Penetration of RFID in low cost item level tagging is hindered due to the high price of tags. The high cost of chipped tags stalled many ambitious projects such as low cost and perishable item level tagging for retails, supply chain management, logistics, pharmaceuticals and luggage handling to just name a few. The tag can be made low cost removing the microchip in the tag. The aim is to make the chipless tag that costs sub cents and is compatible with the current Electronic Product Code (EPC) Global standard. A few research groups have been working in the domain of chipless RFID tags. The big challenge of chipless RFID tag development is to incorporate 64 data bits in a half the credit card size real estate. Recently reported chipless RFID tags can meet neither the bit nor the real estate requirement. The thesis has presented numerous microwave passive designs to develop compact chipless tags with high data capacity. The goal is to develop fully printable uniplanar chipless RFID tags that offer: (i) high spectral efficiency meaning maximum number of data bits possible in the ultra-wide band (UWB) frequency range from 3.1-10.6 GHz, (ii) high spatial efficiency meaning very compact design of multiple data encoding elements in prescribed surface area of the tag, and (iii) operational flexibility such as orientation insensitive tag design. To fulfil the thesis goal a set of high data capacity, spectrally efficient and compact chipless tags are designed. The designed chipless tags are: (i) polarization diversity (PD) based re-transmission type tag; (ii) dual-band modified complementary split ring resonator (MCSRR) based tag; (iii) single polarized radar cross section (RCS) based tag, (iv) dual polarized RCS based tag, (v) multi-dimensional data encoding (MDDE) based tag and (vi) polarization insensitive (PI) tag. To realize the aforementioned chipless tags, a number of compact resonant structures with different polarization attributes, such as single polarized, dual polarized and polarization insensitive, have been proposed. A chipless RFID tag reader is also developed to read the designed tags in a laboratory setting. Successful reading of the designed tags using the developed reader has been accomplished for both mono-static and bi-static tag reading arrangements. The developed chipless RFID system finds potential applications in authentications of Australian polymer banknote and secured documents, tagging of goods and consumables products, bus tickets, stamps, and pharmaceuticals.