Chip impedance characterization for contactless proximity personal cards

Gebhart, Michael; Bruckbauer, Jochen; Gossar, Martin

doi:10.1109/csndsp16145.2010.5580309

Cited by 18 publications

(33 citation statements)

References 9 publications

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“…5,7 Observed from outside, it can be modeled by its input characteristics (C and R IC in Figure 1). 6 During communication, however, the IC continuously adjusts its electrical properties. 12 Consequently, C and R IC depend on the input voltage (U IC ) and, hence, on the input power to the PICC, causing f RES to change as well ( Figure 5).…”

Section: Maximum Re{z Vna }mentioning

confidence: 99%

“…Typical choice is at start-up, which is the point when the IC receives enough energy to turn on. 6 Unfortunately, the start-up point cannot be exactly defined on a VNA because it depends on the chosen IC, antenna, magnetic field strength (H), and so forth. Instead, qualitative definitions based on the Re{Z VNA } curve shape are used, which require Figure 6).…”

Section: Maximum Re{z Vna }mentioning

confidence: 99%

“…A single, unambiguous f RES cannot be defined for contactless chip cards, as it varies with the card's input power. 5,6 Consequently, measuring f RES becomes more complex, 7 specifically due to the need for contactless measurement methods. 2,3 The currently established method for measuring f RES uses VNA measurements for determining the maximum real part of the measured impedance.…”

mentioning

confidence: 99%

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A precise resonance frequency measurement method based on ISO‐standardized setups for contactless chip cards

Pesic

Gruber

Rampetzreiter

et al. 2019

Int J RF Microw Comput Aided Eng

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A method for measuring the resonance frequency of contactless chip cards is proposed in this article. Compared to the vector network analyzer (VNA) based state-of-the-art method, the method gives a more accurate definition of resonance frequency, removes the subjectivity associated with the state-of-the-art method, and makes the measurement integrable into ISO-standardized test setups. Signal processing and system modeling are applied in order to determine the maximum active power in the chip card over a chosen frequency range. This is achieved by using a transfer function obtained from the model and by setting a chirp signal as input to the system. The determined maximum of active power is mapped to the corresponding frequency in the chirp signal, which is defined as the resonance frequency. The proposed method is verified by simulations and by comparing measurement results with the state-of-the-art. The results show that the proposed method offers significant advantages over the state-of-the-art method.

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Section: Maximum Re{z Vna }mentioning

confidence: 99%

Section: Maximum Re{z Vna }mentioning

confidence: 99%

mentioning

confidence: 99%

See 1 more Smart Citation

A precise resonance frequency measurement method based on ISO‐standardized setups for contactless chip cards

Pesic

Gruber

Rampetzreiter

et al. 2019

Int J RF Microw Comput Aided Eng

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show abstract

“…Serial components borrowed from a typical immobilizer application [1] and practically used in automotive vehicles were used as the Tx transmitting coil and Rx receiving coil. A parallel RLC structure (see Figure 2) was used to model them, which took into account the inter-winding capacity, finite resistance in the state of self-resonance, and losses associated with the resistance of windings [12]. Thus, the admittance of the substitute circuit, which describes the above-mentioned structure, can be expressed as…”

Section: Inductive Coilsmentioning

confidence: 99%

“…It should be noted that Equation 7applies to single-winding coils; thus, it is necessary to normalize Eq. (12) in relation to the number of windings N 1 and N 2 . Moreover, dimension x in Equation 8refers to the distance between the coil centers, which is the case of real coils preventing the juxtaposition of the position x = 0.…”

Section: Mutual Inductance M and Coupling Factor Kmentioning

confidence: 99%

2d Disturbance Map of Low-Power Front-End Circuits in Low Frequency Band

Oleszek¹

2019

PIER C

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This document presents an evaluation of a near-field contactless inductive link, examined from a radiated disturbance standpoint, whose sources are low-power Analog Front End (AFE) circuits. Two basic types of AFE rectifiers based on Shottky diodes and Mosfet transistors were tested. Due to selective interference measurement, a map of distortions regarding the position of the coil was created. The obtained results referred to the analytical model, providing sufficient convergence to quickly assess the optimum position of the receiving coil.

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Study on the Reading of Energy-Harvested Implanted NFC Tags Using Mobile Phones

et al. 2020

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In this paper we study the read range of implanted sensors based on batteryless, Near-Field Communication (NFC) integrated circuits (IC) using an NFC-equipped smartphone as a reader. The most important challenges are the low coupling between loops of different sizes, the limited quality factor imposed by the bandwidth communication, the effects of the body on propagation, and the detuning of the antennas. Two systems are analyzed: a conventional system based on resonant coupling between two coils; and a system based on resonant coupling between three coils. With the latter, a relay antenna is attached to a patch, which is adhered to the skin. Simulations and measurements show that the quality factor of both antennas can be improved by including a spacer made of low-permittivity material. A circuit model is proposed for the implanted and relay antenna, which simplifies its usage in circuit simulators. Some implanted and relay antenna prototypes are analyzed and a system model that includes a nonlinear model of the tag is used to analyze the maximum depth at which the implant can be read. Our experimental results show that the system based on three coils performs much better performance at longer distances and is more robust to misalignments between coils. A 15×15 mm-implanted tag with commercial NFC IC and energy harvesting can be read using commercial smartphones. It can feed sensors at a distance of up to 16 mm inside the body and at a distance of 3 cm from the skin. Our results also show that data previously stored in the IC memory can be transferred to the reader located at distances of up to 2 cm and 3.8 cm for the 2-coil and 3-coil systems, respectively. This study demonstrates the potential of batteryless NFC sensors for biomedical and wearable applications using mobile phones as readers. INDEX TERMS Batteryless, energy harvesting, Internet of Things (IoT), implantable medical device, nearfield communication (NFC), radiofrequency identification (RFID), wireless power transfer (WPT).

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Chip impedance characterization for contactless proximity personal cards

Cited by 18 publications

References 9 publications

A precise resonance frequency measurement method based on ISO‐standardized setups for contactless chip cards

A precise resonance frequency measurement method based on ISO‐standardized setups for contactless chip cards

2d Disturbance Map of Low-Power Front-End Circuits in Low Frequency Band

Study on the Reading of Energy-Harvested Implanted NFC Tags Using Mobile Phones

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