Compact multi‐band chipless RFID resonators for identification and authentication applications

Abstract

Moving towards commercialisation of chipless RFID systems, there are still some pressing issues. In the tag design level, the issues are high data capacity in the order of tens of bits, compact design and the immunity to the interference which can be achieved by a cross-polar response. It is demanded to yield the highest numbers of bits in a tag ID while the occupied physical space and allocated bandwidth are minimised. Increasing the number of resonators in a conventional multi-resonator chipless tag causes a significant tag size growth. The destructive coupling effect between resonators in multi-resonator tags is another critical issue. In this Letter, to combat those issues, a multi-band resonator is proposed. The comb-shaped tags contain both co-polar and crosspolar Radar cross section (RCS) responses, hence they can be used in high reflective environments. Two samples of 14-bit and 40-bit combshaped tags are designed, which have physical sizes of 17 mm × 13 and 30 mm × 45 mm, respectively. The promising performance of the proposed structure, which is beyond the state of art hybrid and frequency-domain tags, shows the potential of the proposed designs for identification and authentication applications.

A Novel Design Methodology to Realize a Single Byte Chipless RFID Tag by Loading a Square Open-Loop Resonator With Micro-Metallic Cells

“…In [26], a tag with high spectral efficiency of 7 bits/GHz but low code density of 0.88 bits/cm 2 using non-iterative technique is presented. There are also other recently reported RCS-based tag structures like: L-shaped slot resonator [27], trefoil shaped slot resonator [28] and combshaped tag [29].…”

A 32-Bit Single Quadrant Angle-Controlled Chipless Tag for Radio Frequency Identification Applications

“…The RCS contains encoded information about the tag in question. Several CRFID tags based on these frequency domain (FD) techniques have been proposed [ 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 , 28 , 29 , 30 , 31 , 32 , 33 , 34 , 35 ] to cope with challenges such as: code density, spectral efficiency, conformability, and cost.…”

“…Open-loop-resonator-based CRFID tags [ 27 , 28 , 29 , 30 , 31 , 32 , 33 , 34 , 35 ] have also been reported recently. For example, an 8-bit L shaped tag presented in [ 27 ] has a code density of 4 bits/cm 2 and spectral efficiency of 5.33 bits/GHz.…”

System Development of Calibration-Free 20.7-Bit Chipless RFID Without Iterative Optimization of Tag Configurations

“…While the data can be encoded using frequency [1]- [4], time [5], [6], or hybrid signatures [7], [8], frequency-coded chipless RFID has shown potential of capacity enhancement. The data capacity can reach as high as 28.5 bits [1], 31 bits [2], 40 bits [3], or even 100 bits [4], indicating that billions of IDs are recorded by chipless tags.…”

“…However, the high-capacity frequency-coded chipless RFID has risen to two challenges. First, the chipless tag is comprised of multiple resonators with numerous geometric parameters, such as closed loops [1], U-shaped strips [2], [3], and crossed dipoles [4]. Mutual coupling between resonators makes the synthesis of resonant frequencies require performing iterative full-wave simulations.…”