Design Constraints for NFC Devices

Table of Contents

Cover

Title

Copyright

Acknowledgements

Preface Why and for Whom is this Book Written?

Introduction

PART 1: Introduction to – and Reminders About – NFC

Introduction to Part 1

1 Recap of the Principles Employed in NFC

1.1. The physical fundaments of contactless and NFC

1.2. The concept of NFC

2 Normative Constraints of NFC

2.1. Introduction

2.2. Normative constraints

2.3. Conclusion

3 Regulatory Constraints and Recommendations

3.1. Regulatory constraints specific to NFC and NFC antennas

3.2. Constraints due to recommendations

3.3. Constraints of the NFC market

PART 2: Constraints Due to the Field of Applications of NFC

Introduction to Part 2

4 Applicational Typologies of the NFC and their Consequences

4.1. Applicational typologies of the NFC

4.2. Application consequences and their direct constraints

5 Constraints Due to Fields of Application

5.1. Range of technical possibilities of applications

5.2. Segmentation, typologies of markets, their problems and their incidences, and direct technical constraints on NFC devices

5.3. Mobile telephony

5.4. Banks/money matters/payments

5.5. Transport

5.6. Automobiles

5.7. Healthcare

5.8. Communicating objects

PART 3: Applicational Constraints Needing to be Solved when Designing NFC Systems and their Antennas

Introduction to Part 3

6 Structural Constraints in NFC

6.1. Constraints due to the form factors of the antennas

6.2. Constraints due to variations of the operating distance

6.3. Constraint of the maximum acceptable value of the quality coefficient Q of the initiator antenna

6.4. Constraint of the value of return (retro) modulation voltage

7 Functional Applicational Constraints

7.1. Antenna tuning/detuning constraints

7.2. Constraints and influences of the environment

PART 4: Conformity and Interoperability Constraints

Introduction to Part 4

8 Conformity Constraints

8.1. Conformity tests for NFC devices

8.2. Norms of conformity tests for NFC IPx

8.3. Electrical characterizations of the initiator antenna

8.4. Method of adjustment of the target antenna

8.5. Measuring methods for use with the target

8.6. Electrical measurements of the initiator antenna

8.7. Method for adjustment of whole systems

8.8. Measuring toools

9 Interoperability Constraints

9.1. Norms and interoperability

9.2. Problems of the tests; NCF ISO vs EMV vs NFC Forum etc.

9.3. In practice: a few simple examples of measurements

Conclusion The Near and Far Future of NFC and its Antennas

Bibliography

Index

End User License Agreement

List of Tables

1 Recap of the Principles Employed in NFC

Table 1.1. Relations between the values of frequencies and the distances λ/2π associated therewith

Table 1.2. Variations of the ratio H(a, r)/H(0, r) depending on the values of r and d

2 Normative Constraints of NFC

Table 2.1. ISO terminology for the main contactless transmitters and responders

Table 2.2. Passive, active, remote-powered and battery-assisted functions

Table 2.3. Normative constraints on the design of NFC antennae

3 Regulatory Constraints and Recommendations

Table 3.1. Maximum authorized values in Europe

Table 3.2. Example of SAR for an effective radiated power of around 20 µW

4 Applicational Typologies of the NFC and their Consequences

Table 4.1. Range of application examples

Table 4.2. Range of NFC applications

5 Constraints Due to Fields of Application

Table 5.1. Technical range of applications for NFC and its antenna forms

Table 5.2. Similarities and differences between ATM, POS and mPOS

Table 5.3. Hard and soft constraints remaining to be solved for Transport in NFC

7 Functional Applicational Constraints

Table 7.1. Effect of detuning on the threshold induction and field

Table 7.2. Target in card-emulation mode and alone in the field

Table 7.3. Multiple targets in card-emulation mode in the field

Table 7.4. Initiator in reader mode

Table 7.5. Initiator in peer-to-peer mode

Table 7.6. Table of measurements to be carried out

8 Conformity Constraints

Table 8.1. Official conformity norms and standards

Table 8.2. Characteristics of the coil known as ISO 10373-6 reference coil

Table 8.3. Value of V_induced = f(field H) of the ISO reference coil

9 Interoperability Constraints

Table 9.1. Characteristics of the antenna of the EMV array – TEST PCD

Table 9.2. Example of results

Table 9.3. Estimation of the values of the magnetic fields H_d for the EMVCo antenna

Table 9.4. Example of measurements with a weaker initial field and different loading effects

List of Illustrations

1 Recap of the Principles Employed in NFC

Figure 1.1. Field H at a point on the axis of a circular antenna

Figure 1.2. Curve of the variations in the ratio H(d)/H(0) at a

Figure 1.3. Field H at a point on the axis of a rectangular antenna

2 Normative Constraints of NFC

Figure 2.1. Passive load modulation

Figure 2.2. Active load modulation

Figure 2.3. The different sequences of modified-Miller coding

Figure 2.4. Encoding 1 of 256 for the ASK modulation 10%

Figure 2.5. Position encoding 1 of 4

Figure 2.6. 100% ASK modulation

Figure 2.7. Characteristics of starting and ending carrier modulation

Figure 2.8. Modulation at 10% ASK by an NRZ bit encoding

Figure 2.9. Shapes of transient signals during amplitude jumps

Figure 2.10. Modulation at 10%–30% ASK by a Manchester bit encoding

Figure 2.11. Manchester coded sub-carrier – MSC

Figure 2.12. MCS signal’s OOK modulation action on the carrier

Figure 2.13. Binary phase shift keying

3 Regulatory Constraints and Recommendations

Figure 3.1. ERC 70 03

Figure 3.2. ETSI 300 330

Figure 3.3. Spectral template from Appendix L of ETSI 300 330

Figure 3.4. Respective shapes/values of the spectra for uplink and downlink

Figure 3.5. Examples of ANSES documents (formerly AFSSET)

Figure 3.6. Mandate 436

4 Applicational Typologies of the NFC and their Consequences

Figure 4.1. Passive communication mode

Figure 4.2. Active communication mode

Figure 4.3. Touch & Go, Touch & Confirm, Touch & Connect, Touch & Explore

5 Constraints Due to Fields of Application

Figure 5.1. Routes of marathons and horse races (Photos by Pygmalyon/DAGSYSTEM)

Figure 5.2. Luxury shoe with an NFC chip (Photo by Tagsys)

Figure 5.3. a) Independent antenna within the case of a mobile phone; b) antenna integrated into the battery of a Nexus S mobile phone

Figure 5.4. Transport, mobile telephony and NFC card emulation

Figure 5.5. Example of BMW’s first Connected Key

Figure 5.6. Examples of applications of NFC in the automobile market

Figure 5.7. Example of an NFC antenna (patented) arranged all around the frame. For a color version of the figure, see www.iste.co.uk/paret/nfc.zip

Figure 5.8. Diabetes monitoring with NFC

Figure 5.9. NFC connected bracelets

Figure 5.10. Google’s NFC tablet

Figure 5.11. NFC USB stick (NeoWave document)

Figure 5.12. Communicating and publicity objects for NFC (StrapMedia document)

Figure 5.13. NFC sticker (document from TwinLinx)

Figure 5.14. NFC add-on sticker (documennt from Mercury Technologies)

6 Structural Constraints in NFC

Figure 6.1. DBS modulation in ALM mode

Figure 6.2. ALM signal broadcast by the target antenna

7 Functional Applicational Constraints

Figure 7.1. Equivalent diagram of the HF part of a target

Figure 7.2. Example of variations of H_d_t as a function of ω (or f)

Figure 7.3. Detuning and the off-center tuning technique

Figure 7.4. Variation of detuning as a function of the number of targets

Figure 7.5. Subcarrier frequencies of the return link, target to initiator

Figure 7.6. Input filtering of the return signal

Figure 7.7. NFC device as a target in card-emulation mode

Figure 7.8. NFC device acting as an initiator in reader mode

Figure 7.9. NFC device acting as an initiator in peer-to-peer mode

Figure 7.10. Monostatic antenna configuration

Figure 7.11. Symmetrical rendering using a compensation-loop antenna

Figure 7.12. Antenna shielded by a heavy plate

Figure 7.13. Eddy currents

Figure 7.14. Magnetic shield of plastoferrite

Figure 7.15. Variations of the magnetic permeabilities µ_r’ and µ_r’’ as a function of the frequency

Figure 7.16. Non-exhaustive example of flexible plastoferrite layers

Figure 7.17. Antenna in air, with no shielding or ferrite plate. For a color version of the figure, see www.iste.co.uk/paret/nfc.zip

Figure 7.18. Variety with metal shielding behind the antenna

Figure 7.19. Variety with ferrite behind the antennan

Figure 7.20. Variety with rear ferrite screen. For a color version of the figure, see www.iste.co.uk/paret/t/nfc.zip

Figure 7.21. Example of an antenna shielded by a sheet of ferrite, installed on the metal casing of a mobile phone battery (Google Nexus)

Figure 7.22. Comparison between the different solutions shown above. For a color version of the figure, see www.iste.co.uk/paret/nfc.zip

Figure 7.23. Effects of the positions and relative distances between the metal shielding and the ferrite plate

8 Conformity Constraints

Figure 8.1. Equivalent serial diagram

Figure 8.2. Physical diagram

Figure 8.3. VNA measurements and Smith chart readings

Figure 8.4. Impedance-matching circuits of the antenna

Figure 8.5. Setup used for calibrating the array

Figure 8.6. Example of 700 Ω matching

Figure 8.7. Measuring the detuning and matching settings

Figure 8.8. Interaction of compensation values

Figure 8.9. Smith chart (strictly tunable setup)

Figure 8.10. Shape of voltage at the terminals of the antenna inductance

Figure 8.11. Decrease in field according to the ISO norm

Figure 8.12. Example of conformity with the ISO 14443 -2 A and NFC ISO 18092 norms

Figure 8.13. Measurement of the bandwidth in the application (document provided by Innovision)

Figure 8.14. Measurement tools (documents provided by Micropross and Keolabs)

9 Interoperability Constraints

Figure 9.1. EMV conformity test array

Figure 9.2. Electrical diagram of the EMV array – TEST PCD

Figure 9.3. Nomenclature in the EMV diagram – TEST PCD

Figure 9.4. Antenna of the EMV array – TEST PCD

Figure 9.5. Landing plane (upper part of the plastic plate of the physical plane of the PCD antenna)

Figure 9.6. Operating volume

Figure 9.7. Serial equivalent diagram La, Ra

Figure 9.8. Physical diagram

Figure 9.9. NFC Forum polling devices and listening devices

Figure 9.10. N-Mark logo

Conclusion The Near and Far Future of NFC and its Antennas

Figure C.1. Example of an HF and UHF mono-antenna. For a color version of the figure, see www.iste.co.uk/paret/antenna.zip

Design Constraints for NFC Devices

Dominique Paret

First published 2016 in Great Britain and the United States by ISTE Ltd and John Wiley & Sons, Inc.

Apart from any fair dealing for the purposes of research or private study, or criticism or review, as permitted under the Copyright, Designs and Patents Act 1988, this publication may only be reproduced, stored or transmitted, in any form or by any means, with the prior permission in writing of the publishers, or in the case of reprographic reproduction in accordance with the terms and licenses issued by the CLA. Enquiries concerning reproduction outside these terms should be sent to the publishers at the undermentioned address:

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© ISTE Ltd 2016

The rights of Dominique Paret to be identified as the author of this work have been asserted by him in accordance with the Copyright, Designs and Patents Act 1988.

Library of Congress Control Number: 2016933848

British Library Cataloguing-in-Publication Data

A CIP record for this book is available from the British Library

ISBN 978-1-84821-884-0

Acknowledgements

During my long career in three disciplines – firstly as a professional and industrialist at Philips/NXP Semi-Conductors, secondly and simultaneously as a teacher at numerous engineering schools and universities, and finally, for the past ten years, as founder of dp-Consulting (a firm of consultants and independent technical experts) – I have had the opportunity to meet many experts in this field. Therefore, it is extremely difficult to thank everyone individually to whom thanks are due – that could fill an entire book and more! In addition, as NFC (Near-Field Communication) has such a vast range of applications, it would be fallacious to try to write such a book as this on the subject alone, so my heartfelt thanks go to numerous colleagues and friends:

– from NXP Semiconductors in Graz (Austria), Hamburg (Germany), Monza (Italy), and Caen (France), with whom I have worked for many years;

– customers, partners, and competitors whom I frequently meet at working meetings of the ISO and mirror commissions at AFNOR (France’s standardization body).

In addition, in the coming chapters, I shall occasionally address some specific acknowledgements to various friends for their help.

I also devote this book to the many, many readers who have followed me over the years, through series of publications and technical reports. I owe to you many of these words of gratitude, because it is thanks to you and for you that I have been able to take my courage in both hands to squeeze as much detail out of the subject as possible, with a view to presenting some of its mysteries in as didactic a fashion as possible! In any case, thanks again to one and all for your help and your assiduousness in reading my work. If these few words of thanks have encouraged you to persevere in learning the technique and given you a vocation as a trainer and pedagogue, I would be delighted.

Once again, my true thanks to all of you for your contributions and your faithful friendship.

Preface

Why and for Whom is this Book Written?

Why

Working in the field of NFC (Near-Field Communication) since its very beginnings (a little over 15 years now!), I have written a great deal about this subject in the past. Many advances have been made on the basis of the operational principles, and wonderful and highly varied applications (software) in NFC (particularly with mobile phones). However (there is always a but), there has been relatively little detailed literature produced on the specific functions and the mysteries of application-specific integrated circuits