A High-Gain Passive UHF-RFID Tag with Increased Read Range.

Simone Zuffanelli,Gerard Zamora,Ferran Martin,Ferran Paredes,Jordi Bonache,Pau Aguila

doi:10.3390/s16071150

Abstract

In this work, a passive ultra-high frequency radio-frequency identification UHF-RFID tag based on a 1.25 wavelengths thin dipole antenna is presented for the first time. The length of the antenna is properly chosen in order to maximize the tag read range, while maintaining a reasonable tag size and radiation pattern. The antenna is matched to the RFID chip by means of a very simple matching network based on a shunt inductance. A tag prototype, based on the Alien Higgs-3 chip, is designed and fabricated. The overall dimensions are 400 mm × 14.6 mm, but the tag width for most of its length is delimited by the wire diameter (0.8 mm). The measured read range exhibits a maximum value of 17.5 m at the 902–928 MHz frequency band. This represents an important improvement over state-of-the-art passive UHF-RFID tags.

Highlights

The existence of a tradeoff between physical size and performance has always been a key aspect in UHF-RFID tag design
The read range limitations of passive UHF-RFID tags based on electric dipole antennas have
The read range limitations of passive UHF-RFID tags based on electric dipole antennas have been studied in this work

Summary

Introduction

The existence of a tradeoff between physical size and performance has always been a key aspect in UHF-RFID tag design. Since the free-space wavelength at the UHF-RFID band (840–960 MHz) is of the order of 30 cm, and tag antennas usually work like resonant dipoles, meandering has always been an extensively used technique in order to avoid excessive tag dimensions, allowing the tagging of small items. Whereas for many applications a tradeoff between tag dimensions and performance is necessary, there are some applications where tag performance optimization (i.e., read range) is a due, even at the expense of tag dimensions. Such applications may include, for instance, inventory of boxes in a large warehouse, and pallet tagging, among others. The tag could be sewn into the seams of garments, towels, robe and other textile items, or even directly embedded in their fabric by using conductive thread

Methods

Results

Conclusion