Robust Detection for Chipless RFID Tags Based on Compact Printable Alphabets

Area of Science:

• Electromagnetics and Microwave Engineering
• Materials Science for RF Applications
• Wireless Communication Systems

Background:

• Traditional radio frequency identification (RFID) tags often feature complex geometries, limiting their compactness and printability.
• Visual recognition of transmitted data in real-time via radio frequency (RF) waves is a desirable feature for identification systems.

Purpose of the Study:

• To present a novel technique for designing compact and printable chipless RFID tags using alphabet shapes.
• To analyze the unique frequency response signatures of alphabet-shaped tags for robust identification.
• To investigate the impact of font variations on tag performance.

Main Methods:

• Fabrication of alphabet-shaped chipless RFID tags using copper etching on a dielectric substrate (TLX-8) with a ground plane.
• Simulation and measurement of monostatic radar cross-section (RCS) using a dual-polarized Vivaldi antenna (6-13 GHz).
• Analysis of co- and cross-polar RCS characteristics for different font types, sizes, spacing, and orientations.

Main Results:

• Alphabet-shaped tags exhibit unique dips in their backscattered RCS frequency response, distinguishing individual letters.
• Demonstrated printability and visual recognition capabilities with a coding density of 2.63 bit/cm².
• Achieved good agreement between simulated and measured RCS results for both co- and cross-polarized signals.

Conclusions:

• The proposed alphabet-shaped chipless RFID tags offer a novel, compact, and printable identification solution.
• Utilizing both co- and cross-polar RCS characteristics enhances coding density, security, and detection robustness.
• The method allows for reliable detection of alphabet tags with varying fonts and improved signal-to-noise ratio (SNR).