The Study And Design Of A Novel UHF RFID Near-field Reader Antenna

Recently ultra-highfrequency(UHF)radio frequency identification(RFID),as a technology to identify and track items,comes to various scenarios.Conventionally UHF RFID system is divided into near-field applications and far-field applications based on antenna geometry and electrical size,and UHF near-field system receives more and more attention because of its unique advantage in items-level applications,especially for smart shelf or desktop scenes.In a UHF near-field system,it is a big challenge to maximize the field in a controlled volume close to the reader antenna,under the condition of minute field in the uncontrolled region.Moreover,it requires field enough large in the limited volume as even as possible to avoid failed detections.Now several approaches for the design of near-field antenna have been proposed to make UHF RFID system work at short distances from various objects.One mechanism is based on loop structure to produce strong and uniform magnetic field.Another mechanism based on the structures of microstrip line emerges in recent works.In this paper,we have proposed a novel UHF RFID near-field reader antenna.The antenna configuration,design theory,simulated and measured results have been well discussed.The proposed antenna achieves simultaneously the uniform magnetic field and the uniform linear electric field with a fairly uniform field distribution.The performance of the proposed antenna is verified by fabrication and testing.Good agreement between simulation and measured was presented and the results illustrate that the antenna can perform well in the specific near-field scenarios as well as helpful for professional engineers working on the UHF RFID near-field applications.