Chipless RFID – the end game

RFID tags that do not contain a silicon chip are called chipless tags. The primary potential benefit of the most promising chipless tags is that eventually they could be printed directly on products and packaging for 0.1 cents and replace 10 trillion barcodes yearly with something far more versatile and reliable.
Here, Raghu Das, CEO of independent analysts IDTechEx, reviews the findings of a new report on this very topic.

The mainstream types of chipless tags are digitally encoded and work at more than one millimetre range, like silicon chips. Their potential markets go beyond the lowest cost–highest volume potential markets because they have other attributes beyond cost. Indeed, today they are sold for higher price than silicon chip tags in some cases and lower cost in others. That will continue to be the case. Unique signature, analogue artefacts, such as the magnetically encoded stripe in a banknote or microwave reflecting fibres in security paper, can be sensed at 1mm away and therefore just about fit into our definition of RFID but they have little application beyond anti-counterfeiting. We therefore discuss them only briefly in this report and we omit them from our statistics.

The next decade will see a rapid gain in market share of chipless tags. The numbers sold globally will rise from five million (0.4 percent) in 2006 to 267 billion (45 percent) in 2016. By value, chipless versions will rise from US$1.2 million (0.1 percent) in 2006 to US$1.39 billion – a more modest 13 percent of all income from RFID tags in 2016, because most of the increase in penetration will be by price advantage. Including the infrastructure, software and services, that is a US$2.8 billion market for chipless RFID systems in 2016. Thereafter, chipless tags will rapidly come to dominate the RFID market though the most technically capable chips, such as financial cards containing microprocessors, 5.8 GHz tags for non-stop road tolling or Ultra Wide Band tags for Real Time Location Systems will continue to be made using silicon chips.

Many in play, but few winners

The first generation of chipless technologies did not meet open standards for use by many service providers and no attempt was made to write such standards for them. There were many chipless technologies offered, including acoustomagnetic, swept RF inductor capacitor arrays and electromagnetic RF sputtered film – each a multi-bit version of one of the three types of anti-theft tag in common use. Others have been in the form of diode arrays, surface acoustic wave (SAW) devices and chemicals that emit high frequencies when moved. However, only acoustomagnetic tags for error prevention in healthcare and SAW tags for non-stop road tolling and manufacturing have achieved sales above one million tags. The acoustomagnetic tags of AstraZeneca come out in front and 4.5 million continue to be used every year. However, this design is difficult to cost reduce further and it has performance limitations such as rigidity. The main characteristic of most of the first generation chipless technologies was that they were pursued by small, undercapitalised companies in the main and they had technical limitations that were troublesome in the marketplace.

Welcome to the second generation

In contrast to the above first generation chipless tags, SAW tags can be improved technically and costs greatly reduced. They also store sufficient data and operate at a popular frequency used by conventional chip RFID, which means they can be the basis of large closed and open systems. Indeed, initial work has been done by EPCglobal to incorporate SAW capability in the standards it develops within ISO. Two other technologies are also very promising here. New participants have come up with electromagnetic tags based on nothing more than printed stripes of conductive ink on paper or low cost plastic film. In addition, about 40 companies are working on Thin Film Transistor Circuits (TFTCs) – most of them capable of being printed at high speed on low cost plastic film.

TFTCs can have the same electronic circuit as that in the silicon RFID chip, so, subject to limitations of the materials used, they can employ the same frequencies and standards as chip-based RFID. The ability to operate at 13.56MHz is extremely important as 55 percent of tags ever made have operated at this frequency and the figure will be over 70 percent in 2016.

The main business characteristics of second generation chipless technologies are that they are being backed by some of the world’s largest companies and some well capitalised small ones. Many of them are in a position to be both sellers and users. They include IBM, Hewlett Packard, Xerox, 3M, Toshiba, Dai Nippon Printing, Toppan Printing and Samsung. Packaging and paper giants such as Mreal, MeadWestvaco and International Paper are also involved. However, there are impediments to even these technological routes, as summarised in Table 1. In addition, these technologies also share the attributes of employing non-toxic materials and potentially low cost production facilities compared to silicon.

Best for specific types of application

The most promising chipless technologies will be best directed at certain applicational sectors. Even then, they are not suitable for many opportunities within these sectors and in some such as air baggage and animals the standards are already against them. The best sectors for chipless are nevertheless items (such as books at manufacture, pharmaceutical and consumer goods), smart tickets, banknotes and other high volume secure documents, air baggage, animals, people such as prisoners or those on parole, and high value logistics.

Figure text:

Chipless % of all RFID tags
2006
2010
2016
50
45
40
35
30
25
20
15
10
5
0
Source: IDTechEx

Table 1
Even the most promising chipess RFID technologies face challenges. Benefits and challenges for the most promising chipless RFID technologies

Technology
Benefits actual and potential
Challenges
Main frequency
Typical memory bits
SAW
No threshold voltage so potentially better tolerance of interference and longer range than silicon.
Inherent temperature sensing.
Can do positioning using beams.
Lithographic process with fewer stages than silicon and less precision needed
Hard against a full 10Mrad gamma sterilisation
Exceptional temperature range eg minus 55C to plus 400C
Brittle crystal.
No read write option.
Needs connection to antenna
Scale up to high volume.
Ideal frequency of 2.45 GHz is busy and sensitive to water.
2.45 GHz but UHF is possible
Up to 256
TFTC
Read write and active options. CMOS versions possible to save power.
Low frequency makes it very tolerant of metal and water and range is controllable.
Meeting existing open specifications.
High speed printing directly onto packaging and products.
Suitable for electronic tamper evidence
Could be the basis of an RFID self-adjusting use by date
Special inks needed are currently very expensive.
Conductive inks are not conductive enough.
Not in production.
Initial versions have modest memory and no read write. Large footprint – not suitable for smallest items.
Ultimate potential is a UHF version but may be ten years away. May not be printable on common packaging materials for ten years – currently special grade smooth polyester film is commonly used. Many patents, so royalties may inflate costs. Few of the developers prioritise RFID because the key advantages of distributed low cost manufacture, fast economical turnround of new designs and small numbers are not needed for RFID. Indeed other applications often do not need standards and create new markets with no competition.
13.56 MHz and below
Up to 128
Printed conductive ink stripes
Potentially lowest cost. Can already be made to work on low grade paper and plastic packaging material. Low frequency makes it very tolerant of metal and water and range is controllable.
Probably hard against gamma sterilisation
Some conductive inks change electrical properties permanently if overheated
Suitable for electronic tamper evidence
No read write. No open specifications. Non standard frequency. No active version. Range only a few centimetres. Large footprint precludes use on smallest items.
Up to a few KHz
Up to 128

Source IDTechEx www.idtechex.com

For further information, please do not hesitate to contact Raghu Das, +44 (0) 1223 813703, r.das@idtechex.com

Read the world’s only report covering the future of Chipless RFID, from IDTechEx: Chipless RFID Forecasts, Technologies & Players 2006-2016. For details see www.idtechex.com.