Array sub-loops reader antenna for HF RFID tracking

Megdouda Benamara (1) , Marjorie Grzeskowiak (1) , Miyassa Salhi (1) , Gaelle Bazin Lissorgues (1) , A. Diet (2) , Yann Le Bihan (2)

1 ESYCOM - Electronique, Systèmes de communication et Microsystèmes
2 GeePs - Laboratoire Génie électrique et électronique de Paris

This paper focuses on tracking and objects identification by means of High Frequency magnetic coupling RFID (Radio Frequency IDentification) at 13, 56 MHz. The coil of the used RFID tags corresponds to 1.9% of the reader coil surface (120×160 cm 2 ). To increase the size ratio between the two coils, we proposed the use of multiple twisted loops antenna. The reader antenna is consequently divided into four sub-loops, corresponding to 8% of the surface of each one of the sub-loops area. According to the principle of twisted loop antenna, the nearest sub-loops are feed by current in opposite phase (complementary loops principle), and. This structure creates a strength curvature of magnetic field lines between each two of them, improving the magnetic coupling for vertical magnetic dipoles. In contrast, the structure presents at its center a null of magnetic field intensity due to the symmetry. To avoid this inconvenient a resonator is added to the structure to broke the symmetry and modify the magnetic field distribution. Its positioning is studied to optimize RFID detection in different angular and lateral positioning of the tag. Simulations and measurements of the proposed design with and without resonator are presented in the different parts of this paper.

Keywords: Magnetic coupling; RFID; Mutual inductance; Detection; Array sub-loops antenna

Domains: Engineering Sciences [physics]; Electromagnetism

Megdouda Benamara, Marjorie Grzeskowiak, Miyassa Salhi, Gaelle Bazin Lissorgues, A. Diet, et al.. Array sub-loops reader antenna for HF RFID tracking. 2017 IEEE International Conference on RFID Technology & Application (RFID-TA), Sep 2017, Warsaw, Poland. pp.100-105, ⟨10.1109/RFID-TA.2017.8098892⟩. ⟨hal-01691631⟩