Back to basics

Before you plunge into an RFID purchase, you need to ensure you have at least grasped the basics behind the technology. Here, Ann Grackin, CEO of ChainLink Research, focuses on two fundamental levels to get you up to speed.

First for some really basic definitions. The clever-clogs among you might want to skip ahead to the second section at this point!

Definitions and terminology

Rather than jumping straight into a definition of RFID, I’d like to start our discussion by referring you to Figure 1, which shows how an RFID reader uses radio waves (the same type of energy used to transmit AM or FM signals to your radio) to find or ‘talk’ to the tag. Where RFID is different is that the tag ‘talks back’ by sending back (over radio waves) a unique string of digital data. This is nothing new to us; we come across it every day – radio antennas, TV, cellphones can find and be found through radio or cellular (microwaves.) But only the cellphone can answer back.

We have also had experience of RFID in many stores with tagged items. Today, many approaches are focused on creating unique identification (RFID) the goal of which is to uniquely identify the object on which the tag is attached for the life of that item, or for a specific business event (passing through a dock door, etc.).

Radio frequency (RF) waves are electromagnetic waves that propagate in free space. They can be generated at various frequencies and various distance and carry data such as radio, radar and digital data (digital cell phones, WiFi, etc). RF can operate with low to minimum power at both close range (inches) and longer ranges (hundreds of yards), thus their use in identification and security systems.

The RFID systems are comprised of ‘tags’ and ‘readers’, which are within a reasonable proximity of each other and can send and receive data.

RFID tags
RFID tags are small electronic circuits. Most tags are constructed of a silicon microchip attached to a metallic antenna. The microchip on the tag contains data, the size and type of which can vary depending on the particular application. In some applications today, the data is comprised of a unique serial number and additional space to store application-specific information. It can be a read/write tag that can store data or factory programmed with read only information. The attached antenna allows the data contained on the microchip to be sent to and from a reader device. The explosion of available tags on the market today is mindboggling, both in diversity and number available.

Chipless tags

There is also potential for growth of chipless. Specialised chipless tags are available with relatively small memories, which can be used in extreme temperatures and with very low reader power or long range. These are very early days for chipless tags, but in the long term these types of tags hold great promise because of their low cost. They are likely to replace many barcodes – but not until this wily technology can be tamed and replicated, which may be years.

RFID readers

An RFID reader is an electronic device that has the ability to read and write information to and from RFID tags. RFID readers can be housed in a variety of devices and emit radio waves containing data and commands intended to be received by RFID tags. In ‘passive’ RFID, the radio waves energise the passive RFID tags in the vicinity and cause the tags to be powered on and perform the requested functions. Such functions may include reading serial numbers or other data, writing data or security functions. The interaction with ‘active’ tags is similar, but an active tag is capable of initiating the call as well. More security is being heaped upon readers as well as more intelligence to performance basic applications functions for warehousing, patient care in hospitals, reading passports, etc.

Readers for active technology are frequently devices that also have custom applications. It is not only the traditional reader companies that have high power readers but also PDA and cellphone companies with customisable software. Readers are being embedded in a myriad of other devices and objects, such as automobiles, chairs, toys, etc. Active readers have large wireless ranges, some can communicate directly to the web, for example, and their flexibility in terms of dealing with more remote problems is important.

Readers can be mobile or fixed – mounted in vehicles, on belt buckles, in the floor or pavement, just about anywhere. However, the price of these devices can be high, when bought in mass quantity, so the business application should be carefully considered.

Managing readers

Since they are mobile, authenticating readers and getting them onto your network requires security, both on the part of the reader and your host systems and network. Applications such as RFID middleware, WMS systems and other specialised applications that use RFID or solutions that managed your whole portfolio of wireless devices exist to manage the stable of readers. A little care in setting up security can go a along way to ensure these work seamlessly, from authenticating, operating, managing and, when necessary, de-installing these devices. If the reader falls into the wrong hands, you will want to get it off the network quickly (after all, this is about identity, security and accuracy). So the relationship of the reader to your software solution is critical.

When purchasing RFID, think globally!

Generally, tags have to work across the whole value chain – multiple companies, multiple countries. For products that will move across borders, you need to know your frequencies and standards (we’ll come back to that in a minute). Many products are ISO standard and therefore have global reach (low frequency, high frequency and very high frequency). For EPC Global ‘standards’ – for products moving from Europe to the US, for example – you will need to look at a new approach to RFID (for UHF/Passive) called ‘wideband’. So far, only a few tag vendors, Avery Dennison and Intermec, have this feature. Their approaches with wideband are different, so you will have to know what your applications are.

In general readers tend to be a corporate rather than a site decision, because, again, you want to manage their entrée into your network. Today, many devices used for barcoding are bought at a local level, so this will be an unwelcome change for both site manager as well as vendors. Who wants to involve more people in the buying decisions! But security is a very important consideration as we use these devices ubiquitously.

The RFID market – primary positioning

There isn’t the space to provide you with the kind of technical background you need to really delve into RFID, but you can begin to think about your needs and who might be a good provider.
For end users: One important element of the RFID market relates to the application. We bring this up, since you can get RFID not only from pure play providers, but also firms who provide infrastructure, such as material handling, containers and pallets, printer companies, etc. Though many applications will require discussions with pure plays, in many cases, RFID will be a component of an overall programme.

For solution providers: RFID provides fabulous opportunities for expanding product lines, offering new products and enhancing existing services. For these kinds of firms, the market can be viewed as a college of partnership

As RFID opportunities grow, many vendors will provide many frequencies, active and passive. But, most vendors have focused expertise in a particular set of products.

Selecting the right tags, frequencies and applications

All the noise lately has been about the passive technologies. With the promise of ultra-low cost, they do represent certainly an attempt at a ubiquitous solution. Active technologies provide you range of visibility, data rich devices that can be used over a lifetime, etc. They also have a proven ROI in the closed-loop application areas they have been in use for many years. But like all good things, it comes with some challenges.

Final thoughts

While in this short article we have barely scratched the service of RFID, a basic vocabulary and some common sense can help. RFID use and implementation is both an art and a science. We recommend that you start the learning process if you are planning to go down the path of purchase and implementation. The greater the knowledge, the lower the risk involved.

RFID TERMINOLOGY

RFID Tag/Transponder
A microchip attached to an antenna (there are also chipless tags) that picks up signals from and sends signals to a reader.
From one-bit tags to data rich tags, these can store data such as unique serial numbers, location information, and many other types of data.

Antenna
The antenna is the conductive element that converts RF into electrical energy and vice versa, thereby enables the tag or reader to send and receive data wirelessly. Antennas can be wire, etched conductive or conductive inks made from aluminium, copper or silver.

Reader/Interrogator/Encoder
The reader (also called an interrogator) communicates with the RFID tag via radio waves and reading (interrogator) as well as writing information (encoder) to and from the tag. A reader may store the data and/or passes the information in digital form over the network or directly to another device. Readers may also receive data from other sensory devices (e.g. motion detector) and/or they may control other devices (such as indicator lights).

Active Tag
An RFID tag that contains its own power source. This power source is used to power the microchip, and receive and transmit data. Active tags can be read and great distances (RFID tags at hundreds of feet or yards. Wireless tags at kilometers, and GPS for many kilometers). Active tags are frequently combined with devices like sensors or GPS.

Passive Tag
A passive tag has no power of its own. An RFID tag is powered solely by the RF energy emitted by the reader device. The passive tag uses this energy to power the microchip and transmit data back to the reader. Read distances are limited due to the power fall-off which happens fairly quickly. In other words, passive tags can receive and transmit data only over several feet.

Debunking the myths

Myths
Comments

Passive tags are cheaper
The sensible way to think about cost is cost-per-use, rather than cost-per-tag Users need always to think about the application they intend to use RFID for. Returnable totes, reusable or closed loop applications, tracking high value items and asset management, and locating item in environments that are out of range, all are active uses for active technology! Rugged and reusable, these are cost/benefit factors.

Passive tags will soon be cheaper
RFID, even with mass deployments, does not even make one percent of the total market for the semiconductor industry. In the semiconductor industry, where many believed in Moore’s Law (cost comes down by 50 percent every year or two) this concept applies to large return on investments for the industry based on scale. However, with less than one percent of the capacity dedicated to RFID, Moore’s Law probably won’t apply.

Also if you look at the basic evolution from the beginning, Sensitech and Checkpoint one-bit tags, to the current Gen 2 96 bit (byte) tags, the compounding on intelligence on the tag the trend is for more capabilities – therefore as the old tags price goes now, the new tags will be higher priced.

Large contracts will, though, naturally though provide lower prices.

Until we see those breakthroughs (e.g. printed tags), the dream of a five-cent tag is a distant is myth.

Passive tags are not reusable
Again, a hilarious myth. Ruggedised tags can be housed in material such as plastic, for example. Certain material used for inlays and packaging withstand very high temperatures and harsh chemicals.

Items use passive tags exclusively, not active tags
Computers, Gucci handbags, Louis Vuiton luggage, artwork, auto parts, or food are all items! These might need refrigerator totes, real time active tracking, or authentication. Medical equipment is items – and we really want to find these when we need them – and also items. These items can range from US$10.00 to millions of dollars. The value of the item or more importantly the process they enable, places a high value on rapid identification and location provided through active technology.

RFID cannot be used in the home- or there is no home market for RFID
Think of your cellphone, PDA, your free wi-fi device, or even set-top box as potential RFID readers. They are everywhere. The features come free – remember the camera, the MP3, etc., on your cellphone? We are already seeing RFID readers embedded in toys, stoves and other home devices. And we do want to track our kids! I think this drives home the point.