Calculation of the equivalente mutual impedance in complex HF RFID systems

Benamara, Megdouda; Grzeskowiak, Marjorie; Lissorgues, Gaëlle; Diet, Antoine; Bihan, Yann Le; Conessa, Christophe

doi:10.1109/icecom.2016.7843884

Cited by 3 publications

(10 citation statements)

References 6 publications

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“…In HF RFID systems, the mutual inductance is calculated from the magnetic coupling between the reader and the tag coils. In this part of HF RFID system the communication corresponds to the conventional link of near field communication: the mutual inductance can be calculated from the impedance matrix parameters [12]. To calculate the mutual inductance between the MTLA and the tag, the electrical model of the system is used (Fig.3).…”

Section: B Mutual Inductancementioning

confidence: 99%

“…In the case of the array sub-loops antenna, the mutual inductance is transformed to the equivalent mutual inductance [12]. Its calculation is based on the mutual inductance between the MTLA and the tag, the mutual inductance between the resonator and the tag, the mutual inductance between the MTLA and the resonator and all the electrical parameters of the system.…”

Section: B Mutual Inductancementioning

confidence: 99%

“…In this case, optimizing the tag detection is currently done by changing the shape of the conventional (circular or rectangular) reader coil. In the context of small misaligned tag, several studies are proposed to improve RFID detection [6][7][8][9][10][11][12]. In [12] reader antenna including resonator is proposed.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Array sub-loops reader antenna for HF RFID tracking

Benamara¹,

Grzeskowiak²,

Salhi³

et al. 2017

2017 IEEE International Conference on RFID Technology &Amp; Application (RFID-TA)

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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 (120x160 cm²). 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.

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Section: B Mutual Inductancementioning

confidence: 99%

Section: B Mutual Inductancementioning

confidence: 99%

See 1 more Smart Citation

Array sub-loops reader antenna for HF RFID tracking

Benamara¹,

Grzeskowiak²,

Salhi³

et al. 2017

2017 IEEE International Conference on RFID Technology &Amp; Application (RFID-TA)

Self Cite

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“…DDC (Distributed Diameter Coil) resonator maintains the efficient coupling in 3D spatial variation (distance and location) above its surface in comparison with a conventional coil. The advantages of coplanar coupled resonator in a coil [15] are combined with the optimization of the distribution of each coil of the resonator [16] to improve the RFID detection for a small tag (in comparison with the size of the reader coil).…”

Section: Introductionmentioning

confidence: 99%

“…In the following section, DDC resonator is inserted in the center of a reader rectangular coil [15] whose size determines the detection area. The coupling coefficient between the reader coil (including DDC resonator) and a small tag coil is shown to be increased.…”

Section: Introductionmentioning

confidence: 99%

Enhanced Hf Rfid Detection Area of Mobile Small Tag via Distributed Diameter Coil Resonator

Grzeskowiak¹,

Diet²,

Benamara³

et al. 2018

PIER C

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To improve HF detection of small RFID tags, a Distributed Diameter Coil (DDC) resonator is included in the reader coil. The key ideas of detection improvement are twofold: using a resonator with Magnetic Resonant Coupling (MRC) and modifying the distribution of diameter and current for each loop of the DDC resonator. These factors allow the magnetic coupling to increase between the reader and the smaller tag, especially in our case where the effective area of the tag is below 0.1% of the reader coil surface. Numerical simulations are carried out using HFSS to confirm the enhancement of the mutual coupling between the tag and the reader coil: the coupling coefficient is used in doubleloop coupling (the case of the coupling of two loops), when a third loop (resonator) is inserted. The optimization of the magnetic coupling between a large reader and a small tag with resonator could be realized in changing first the sub-coil diameters, and then the sub-coil number of turns. One figure of merit to quantify the ability of surface detection is defined. A 15% improvement of detection surface in Horizontal Mode is measured at 1 cm of the reader plane in comparison with a conventional coil. Experimental detection measurements on real structures are described to validate statements.

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Effect of added resonators in RFID system at 13.56 MHz

Benamara

Grzeskowiak

Diet

et al. 2018

IET Microwaves, Antennas & Propagation

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In this study, a reader antenna including resonators is proposed to improve detection of a small moving tag in the case of tracking a radiofrequency identification (RFID) system. The near-field RFID technology is based on load modulation, the input impedance on the reader coil and the mutual inductance between the reader and tag coils are the main parameters for performing detection. They are calculated from the impedance matrix parameters. The added resonators change all the parameters of the impedance matrix consequently the input impedance and mutual inductance are also changed. In this study, analytical formulation defining the equivalent impedance matrix parameters is developed. These formulae are used to evaluate the performance of the proposed design according to the tag misalignment (lateral and angular). From the calculation and simulation results, a frequency shift in the equivalent input impedance is found. To avoid this problem, optimising the positioning of the resonators on the reader coil is performed. This study is confirmed by measures of RFID detection for a reader prototype (with and without resonators) and a small commercial tag. Both the surface and volume of detection of the small moving tag (lateral and angular misalignment) are improved by the principle of added resonators.

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Calculation of the equivalente mutual impedance in complex HF RFID systems

Cited by 3 publications

References 6 publications

Array sub-loops reader antenna for HF RFID tracking

Array sub-loops reader antenna for HF RFID tracking

Enhanced Hf Rfid Detection Area of Mobile Small Tag via Distributed Diameter Coil Resonator

Effect of added resonators in RFID system at 13.56 MHz

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