ISO/IEC TR 18268:2013

Identification cards - Contactless integrated circuit cards - Proximity cards - Multiple PICCs in a single PCD field

ISO/IEC TR 18268:2013 presents a collation of industry experience of technical issues resulting from the presence of multiple PICCs (proximity card or object) in the field of a PCD (proximity coupling device). It describes how resonance frequencies may shift, how individual PICCs may see a reduced field strength, how multiple PICCs load the PCD, how they may change the local modulation signal and how PICCs should manage their identities to aid support of simultaneous usage. Scenarios for electronic passports with multiple visas and wallets containing multi-industry cards are explored.

Cartes d'identification — Cartes à circuit(s) intégré(s) sans contact — Cartes de proximité — Multiples PICCs dans le champ d'un seul PCD

General Information

• Status: Published
• Publication Date: 09-Dec-2013
• ICS: 35.240.15 - Identification cards. Chip cards. Biometrics
• Technical Committee: ISO/IEC JTC 1/SC 17 - Cards and security devices for personal identification
• Drafting Committee: ISO/IEC JTC 1/SC 17 - Cards and security devices for personal identification
• Current Stage: 6060 - International Standard published
• Start Date: 10-Dec-2013
• Due Date: 13-Apr-2015
• Completion Date: 13-Apr-2015

Overview

ISO/IEC TR 18268:2013 is an informative Technical Report that collates industry experience on the technical effects and practical issues when multiple PICCs (proximity integrated circuit cards or objects) are present in the field of a single PCD (proximity coupling device). The report explains how multiple contactless integrated circuit cards interact electromagnetically - including shifts in resonant frequency, reduced field strength, loading of the PCD, distortion of modulation signals, and identity-management considerations to support simultaneous usage. Typical scenarios such as electronic passports with multiple visas and wallets containing multi‑industry cards are examined.

Key Topics

• Resonance shift: Mutual inductive and capacitive coupling between PICC antennas lowers the collective resonant frequency (relative to individual PICCs). The report explains how collective resonance moves toward and below the 13.56 MHz operating frequency as the number of PICCs increases.
• Lowest operating field strength (Hlow): Multiple, closely coupled PICCs present a lower collective Q factor and may require a higher local magnetic field strength for reliable operation. The document models Hlow vs. number of PICCs in three practical regions.
• Loading effect on PCD: Presence of one or more PICCs alters PCD antenna current and Q factor; this affects operating volume and power available to cards.
• Signal/modulation distortion: Multiple PICCs can modify the PCD waveform (modulation index, rise/fall, ringing), impacting both PCD→PICC and PICC→PCD communication quality.
• Addressing & identity management: Recommendations on how PICCs should manage identities and addressing (e.g., CID support, UID/PUPI handling, AFI management) to aid collision avoidance and predictable selection.
• Empirical scenarios and test considerations: Practical examples (passports, wallets) and implications for system behaviour and user experience.

Applications and Who Uses It

ISO/IEC TR 18268:2013 is practically valuable to:

• Card and antenna designers (optimize PICC resonant tuning and antenna layouts)
• PCD/RFID reader manufacturers (design robust readers with adequate power and modulation resilience)
• System integrators and solution architects (design workflows for multi‑card interactions in access control, ID and payment)
• Government ID programs (e-passports) and wallet manufacturers (assess multi‑card presentation scenarios)
• Test labs and standards bodies (develop test methods and interoperability guidance)

Use this report to improve user experience and reliability where simultaneous presentation of multiple contactless cards is likely.

Related Standards

• ISO/IEC 14443 (contactless smart card standard referenced in the report)
• ISO/IEC 10373-6 (test PCD assembly and test methods used in simulations)

Keywords: ISO/IEC TR 18268:2013, contactless integrated circuit cards, proximity cards, PICC, PCD, resonance frequency, field strength, loading effect, electronic passport, multi‑industry wallet.

Standards Content (Sample)

TECHNICAL ISO/IEC
REPORT TR
First edition
2013-12-15
Identification cards — Contactless
integrated circuit cards — Proximity
cards — Multiple PICCs in a single PCD
field
Cartes d’identification — Cartes à circuit(s) intégré(s) sans contact —
Cartes de proximité — Multiples PICCs dans le champ d’un seul PCD
Reference number
©
ISO/IEC 2013
© ISO/IEC 2013
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized otherwise in any form
or by any means, electronic or mechanical, including photocopying, or posting on the internet or an intranet, without prior
written permission. Permission can be requested from either ISO at the address below or ISO’s member body in the country of
the requester.
ISO copyright office
Case postale 56 • CH-1211 Geneva 20
Tel. + 41 22 749 01 11
Fax + 41 22 749 09 47
E-mail [e-mail]
Web www.iso.org
Published in Switzerland
ii © ISO/IEC 2013 – All rights reserved

Contents Page
Foreword .iv
Introduction .v
1 Scope .1
2 Symbols and abbreviated terms .1
3 General .1
4 Physical effects of multiple PICCs .2
4.1 Resonant frequency . 2
4.2 Lowest operating field strength H . 5
low
4.3 Loading effect . 6
4.4 PCD to PICC communication . 7
4.5 PICC to PCD communication . 7
5 Addressing multiple PICCs .8
5.1 CID support . 8
5.2 Altering random UID or PUPI . 8
5.3 Receiving blocks of other type . 8
5.4 AFI management . 8
6 Scenarios .9
6.1 Passport - multiple visas . 9
6.2 Wallet - multi-industry . 9
6.3 Possible scenarios .10
6.4 Collision avoidance .10
Bibliography .11
© ISO/IEC 2013 – All rights reserved iii

Foreword
ISO (the International Organization for Standardization) and IEC (the International Electrotechnical
Commission) form the specialized system for worldwide standardization. National bodies that are
members of ISO or IEC participate in the development of International Standards through technical
committees established by the respective organization to deal with particular fields of technical
activity. ISO and IEC technical committees collaborate in fields of mutual interest. Other international
organizations, governmental and non-governmental, in liaison with ISO and IEC, also take part in the
work. In the field of information technology, ISO and IEC have established a joint technical committee,
ISO/IEC JTC 1.
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.
The main task of the joint technical committee is to prepare International Standards. Draft International
Standards adopted by the joint technical committee are circulated to national bodies for voting.
Publication as an International Standard requires approval by at least 75 % of the national bodies
casting a vote.
In exceptional circumstances, when the joint technical committee has collected data of a different kind
from that which is normally published as an International Standard (“state of the art”, for example), it
may decide to publish a Technical Report. A Technical Report is entirely informative in nature and shall
be subject to review every five years in the same manner as an International Standard.
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. ISO and IEC shall not be held responsible for identifying any or all such patent rights.
ISO/IEC TR 18268 was prepared by Joint Technical Committee ISO/IEC JTC 1, Information technology,
Subcommittee SC 17, Cards and personal identification.
iv © ISO/IEC 2013 – All rights reserved

Introduction
Experience from the field has shown that the presence of multiple PICCs in a field can have unexpected
results in terms of all PICCs being seen by the PCD and the quality of the communications. This Technical
Report seeks to assemble the collective knowledge of the engineering principles involved.
This Technical Report is relevant to the standards listed in the Bibliography and an understanding of
these is useful in placing this Technical Report in context.
© ISO/IEC 2013 – All rights reserved v

TECHNICAL REPORT ISO/IEC TR 18268:2013(E)
Identification cards — Contactless integrated circuit cards
— Proximity cards — Multiple PICCs in a single PCD field
1 Scope
This Technical Report presents a collation of industry experience of technical issues resulting from
the presence of multiple PICCs in the field of a PCD. It describes how resonance frequencies may shift,
how individual PICCs may see a reduced field strength, how multiple PICCs load the PCD, how they
may change the local modulation signal and how PICCs should manage their identities to aid support
of simultaneous usage. Scenarios for electronic passports with multiple visas and wallets containing
multi-industry cards are explored.
2 Symbols and abbreviated terms
f resonant frequency
r
H lowest magnetic field strength
low
Q quality factor
PCD proximity coupling device
PICC proximity card or object
3 General
In order that multiple PICCs can be reliably presented to a PCD, the following should generally be
achieved:
a) PICCs presented (within the PCD’s operating field) need to receive sufficient power to operate.
b) The communications interface between each PICC and the PCD needs to operate reliably (for all
PICCs within the PCD operating field).
c) The PCD should perform its intended functionality in a manner such that the cardholder experience
is reliable and consistent.
In an operational contactless interface, there are a number of components that have a mutual interaction.
The most dominant of these is the inductive coupling between the coil of the PCD antenna and that of
the PICC, plus further interaction between all the PICC antennas if there are multiple PICCs within the
field. The interaction is multi-faceted and depends on the coupling factor k between each inductance, the
resonant frequency f of the individual PICCs and the quality factor Q of all of the inductive components.
r
Other factors which also have an impact are the size of antenna, separation distance, spatial overlap,
PICC loading and the dynamic movement of PICCs through the PCD field.
With so many degrees of freedom, it is not possible to describe the definitive outcome for any particular
combination of PICCs presented to an individual PCD. However, it is possible to quantify certain aspects
with the objective of gaining an improved understanding of the mechanisms involved. This is expected
to lead to recommendations and potential revisions to the standards that will ultimately improve the
acceptance of multiple PICCs presented to a single PCD. The main items that can be addressed are:
— the PICC interaction such that the resulting resonant frequency of the set of PICCs is lower compared
to the resonant frequency of an individual PICC;
© ISO/IEC 2013 – All rights reserved 1

— the uneven sharing of power between the PICCs in the field, such that some may receive insufficient
power to operate correctly;
— the influence on PCD modulation caused by close coupled PICCs, such that collectively, multiple
PICCs in the field will receive a modified modulation signal shape.
In order that contactless products continue to have practical application, the reliability and consistency
of the user experience needs to be addressed in the following areas:
— The PCD should be able to reliably build a list of applications available on the presented PICCs and
determine in a consistent manner an order for which it will attempt to undertake its intended
function.
— This process should be easy to understand by the general public and consistent across PCDs such
that the user feels in control.
— The user interface on the PCD should provide simple feedback to the user, such that they understand
when the intended function is completed, or if an issue has occurred.
— Overall performance (speed of operation) should not be reduced significantly when multiple PICCs
are presented such that the usability of the functionality is compromised.
4 Physical effects of multiple PICCs
4.1 Resonant frequency
When operating within an electro-magnetic field of given frequency, then maximum power coupling
would occur if PICCs are tuned to have a resonant frequency equal to the operating frequency of the
field. However, typical PICCs are manufactured to have a resonant frequency higher than the operating
frequency (13,56 MHz) to limit the loading effect on PCDs.
When the antenna of a PICC is close to another antenna there will be a drop in its resonant frequency ( f ).
r
This is due to the capacitive coupling and mutual inductance that forms between the turns of the coils
of the two antennas. From the formula f = 1/(2π√LC), if either the capacitance or inductance increases,
r
then the frequency will drop. Both the antenna in the PCD and the antennas of other PICCs in the field
will cause this effect. Generally the coupling to a physically adjacent PICC (or PICCs) will be more than
that to the PCD antenna.
Figure 1 and Figure 2 show this effect as evaluated experimentally for ISO/IEC 14443 operation using
multiple PICCs all having an individual resonance frequency of about 20 MHz.
2 © ISO/IEC 2013 – All rights reserved

1 PICC
2 PICC
3 PICC
05 10 15 20 25 30 35
f (MHz)
Figure 1 — Power drop and resonance shift
Individual
resonance
frequency
13,56 MHz
16 MHz
19 MHz
22 MHz
33 MHz
13,56 MHz
1234 56 78 91011121314151617181920
Number of PICCs
Figure 2 — Collective resonance frequency vs number of PICCs
© ISO/IEC 2013 – All rights reserved 3
Collective resonance frequency (MHz)
Voltage on chip (V)
Figure 1 and Figure 2 curves are from a simulation based on the ISO/IEC 10373-6 Test PCD Assembly
with a distance between PICC antennas of 1 mm and using the test PCD antenna and PICCs with “Class 1”
antenna size as shown in Figure 3.
3,&&Q3,&&Q
3,&&3,&&
PPPP
3,&&3,&&
PPPP
3,&&3,&&
PPPP
PPPP
7HVW3&'DQWHQQD7HVW3&'DQWHQQD
PPPP
&DO&RLO&DO&RLO
a) Schematic b) Physical
Key
L antenna inductance
R series resistance
s
C parasitic capacitance
p
I chip input current
th
V chip threshold voltage
LaLb.th
Figure 3 — Simulation set-up
Virtual simulation of the coupling indicates that the capacitance between two resonant circuits has a
strong influence on the measurable effects of the two circuits being coupled. With coupling between only
the inductances, then the frequency response shows that the uncoupled resonant frequency separates
into two new peaks spaced equally higher and lower than the uncoupled frequency. However, circuits
in a real system will also have capacitance between them. This tends to suppress the higher frequency
peak as the capacitance increases, with the result that the collective resonant frequency appears to be
lowered. Figure 4 shows this effect.
4 © ISO/IEC 2013 – All rights reserved

Small c
Mid c
High c
10 11 12 13 14 15
f (MHz)
Fi
...