Double Loop Inductive Feed Patch Antenna Design for Antimetal UHF RFID Tag

Lingfei Mo,Chenyang Li

doi:10.1155/2019/2917619

Abstract

Planar UHF RFID antimetal tag can be widely used for the metallic products or packages with metal material inside. A double loop inductive feed planar patch antenna is proposed for UHF RFID tag mounted on metallic objects. Compared to conventional microstrip antennas or PIFA antennas used for UHF RFID tags, the double loop inductive feed patch antenna has a planar structure, with no short via or short wall, which could decrease the manufacturing cost of the tags. The double loop inductive feed structure also increases the radiation performance of the planar antenna. Moreover, the double loop inductive feed structure makes the impedance of the patch antenna be tuned easily for conjugate impedance matching.

Highlights

Radio frequency identification (RFID) in the ultrahigh frequency (UHF) band is gaining more and more attention recently because of its long read range, fast read rate, and low cost
The UHF RFID tags are required attaching to the surface of metal objects, for instance, steel cups and packages with metallic foil inside
It is difficult for the UHF RFID tags to work properly on the surface of metal objects, especially when the tags are with dipole label-type antennas

Summary

Introduction

Radio frequency identification (RFID) in the ultrahigh frequency (UHF) band is gaining more and more attention recently because of its long read range, fast read rate, and low cost. Few planar patch antennas are designed for the metal environment [20, 21], using a big ground plane or open stub feeding structure Most of these planar tag antennas have low radiation efficiency and are difficult for impedance matching. There are some flexible planar tag antennas, such as the flexible wideband UHF RFID tag antennas for curved metal surfaces and the low profile flexible metal mountable UHF RFID tag antennas [24] These designs are simple and without shorting pins for interconnecting, it has the shortcoming in radiation efficiency and impedance matching [24, 25]. The experiment results show that the planar UHF RFID tag patch antenna with a double loop inductive feed has a good radiation performance and flexible impedance matching ability when used on metal

Antennas Design

Simulation

Measurement Methods and Results

Conclusions