One terminal improving method of open-circuit near-field antenna of UHF RFID system

Abstract

A novel broadband dual-loop antenna is presented for the ultra high frequency (UHF) near-field radio frequency identification (RFID) applications. Owing to the novel structure, the current distribution along the loop is kept in phase, as well as the metal terminals exert less influence on the z-orientation magnetic field. The antenna with novel terminals is described and the principle of operation is explained. A comprehensive parametric study of the new model is carried out and the results are presented and discussed in detail. To prove the novel structure, a prototype is developed and fabricated. The measurement results demonstrate that the antenna could achieve a broad bandwidth and low gain, and produce a strong magnetic field with a relatively small z-orientation magnetic field empty hole in the near field. Hence, the work is very promising for UHF near-field RFID reader applications.

Keywords:

• UHF
• RFID
• near field
• inductance-like terminal
• broadband
• dual-loop antenna

Acknowledgements

This work was supported in part by the National Natural Science Foundation of China (No. 60802083, and 61271416), the National Defense Pre-Research Foundation of China (No. 11055132535), and the NPU Foundation for Fundamental Research (NPU-FFR-JC200817).