Diversity: Hallmark of RFID

RFID first hit the market in the 1970s and has seen continued improvements over the years, making it an effective technology for tracking and managing goods with applications in a variety of vertical markets. RFID exists in different types and forms. Chief among them are LF, HF, UHF, active, and passive RFID, each with unique applications in different verticals. This article chiefly examines the technology behind long-range RFID.

RFID, or radio-frequency identification, can trace its history to after the Second World War, when devices transmitting and retransmitting radio waves carrying audio information were invented for covert operations. The first true RFID device, a passive transponder with memory, was unveiled in 1971 and patented in 1973.

While RFID is not a new concept, it has never gone out of style since its introduction in the last century. From parking lots to highways, factories to offices, RFID can now be found in various parts of our everyday life. According to IDTechEx, the RFID market is worth US$8.9 billion in 2014, a rise from $7.8 billion in 2013 and $7 billion in 2012. The figure is expected to rise to $27.3 billion By 2024. The market research firm also predicts 6.9 billion tags will be sold by the end of 2014 — versus 5.8 billion in 2013 — to retailers, event organizers, and animal farmers, among others.

RFID's popularity has to do with its ability to effectively identify, manage, and track goods, in the process saving businesses a huge amount of money in labor and management costs. The technology works by way of communication between a reader and a tag and generally includes the following features:

1. Read-Write: Data stored in the tag can be read, without any contact, by the reader, which can read multiple tags at the same time. Meanwhile, data can also be written into the tag for operators to know the status of the order or delivery process.

2. Diversity in shapes and sizes: Unlike paper labels which come in specific sizes, RFID isn't limited by the size of the tag, which can be in different shapes and be as small as possible.

3. Resistance to dirt/stains: Unlike paper labels, which become unreadable when dirtied or soiled, RFID tags don't have this problem.

4. Reusability: Since data stored in the tag can be overwritten, the tag can be reused over and over again on different products.

5. Bigger memory: A barcode contains 50 bytes of data, while an RFID tag can contain several megabytes of data.

Diversity Rules
RFID comes in many forms, each with its special features and applications. The technology can be categorized in two ways: by the frequency of the signal transmitted (low-frequency, high-frequency, and ultrahigh-frequency RFID), and by whether there is power in the tag itself (active RFID vs. passive RFID).

LF RFID
This technology employs the 9kHz to 135kHz band of the radio spectrum. It is limited by the reading distance, which is approximately 1.5 meters. Limited memory capacity is another disadvantage with this type of RFID. However, there are several advantages as well, one of which is its immunity to metal or wet environments. Meanwhile, since this frequency band is open in most countries, there are fewer regulatory issues. Applications are mostly in animal management on farms, access control, and theft prevention.

HF RFID
HF RFID uses the 13.56MHz frequency band. It is also limited by the reading range of 1.5 meters, and there are different standards applied to this particular RFID. However, HF RFID is a highly accepted technology with different applications, for example access control payments, automation, asset tracking, library management, and electronic airline tickets. “HF RFID allows high flexibility as well as good stability and security,” said Klaus Klosa, MD at LEGIC Identsystems.

UHF RFID
UHF RFID signals range from 300MHz to 1.2GHz. The reading distance is not limited by 1.5 meters and can go anywhere from 1 centimeter to 15 meters. The technology is also well-standardized. Disadvantages include susceptibility to the environment. Interference when overlapping with devices using the same frequency range may also happen. In fact, this frequency band is banned for commercial use in Japan.

Despite all this, UHF RFID has enjoyed strong growth, especially in areas, such as retail, where strong inventory visibility is needed. “UHF technology is strongly growing compared to other frequencies due to its high performance and good standardization,” said Richard Aufreiter, Director of Product Management at HID Global.

Active vs. Passive
The method of powering the RFID tag differentiates between active and passive RFID. Active RFID uses an internal power source, such as a battery, within the tag, which can transmit signals to the reader. Passive RFID, meanwhile, uses tags that rely on the energy from the reader to stay active.

Each has its advantages and disadvantages. For active RFID, the read range is significantly longer and can go as much as 100 meters. On the negative side, the tag is limited by battery life and can be quite expensive, ranging from $15 to $100 per tag as opposed to passive tags that cost anywhere between 15 cents to $5. Applications include real-time tracking or any systems where high-volume assets are moving within designated areas. Passive RFID, meanwhile, literally “sleeps” when not being powered by a reader field. It's low-cost and requires only minimal maintenance fee. Its best area of use is moving high-volume assets through a fixed point. “All ‘typical' RFID applications are those that do not require active tags,” Aufreiter said.

Tags and Readers
Tags come in different sizes and shapes, from those the size of one's fingernail to those comparable to Christmas cards — although the trend is moving towards making tags smaller and smaller.

Tags can be worn as wristbands, embedded in tickets, placed on cargoes, and inserted in clothes. In other words, users should pick tags that suit their needs and purposes. In terms of the materials that the tags are made from, they are also diverse and wide-ranging as the tags themselves. “Typically materials differ in heat, cold, UV, flame or chemical resistance, rigidity or flexibility, and cost. Depending on the use case, the proper tag housing material is chosen by the manufacturer,” Aufreiter said.

Readers consist typically of the reader module and the antenna. “Some readers support more than one concurrently connected antenna or have the processing power and flexibility to do certain calculations with the data read internally, so that the network and SAP system in the back does not have to deal with raw data but receives already consolidated results,” Aufreiter said.

Things to Look for in Implementations
One thing people need to understand about RFID is that the experience can't be duplicated. “You finish one project, you take this project model and copy to the next project, and make a quick profit — that simply doesn't work,” said Brian Ma, Sales Representative at GIGA-TMS. “Each scenario is different. Every project is customized.”

It is therefore necessary to sit down with clients and talk about what they want to achieve with RFID. “Work closely with the end users of the solution in the field, so that they can see the benefit of the new solution and give you valuable feedback. Do not only look at tag and reader costs alone, but calculate the ‘bigger picture' for costs and benefits,” Aufreiter said.

Technically, “installers need to keep in mind the positioning of antenna and if enough care is been taken to shield from the environment where the installation is being done,” said Atul Ghaisas, Business Development Manager of Store Performance Solutions for APAC at Tyco Retail Solution. “The distance between the reader and the antenna should be based on the manufacturer's recommendations and should not be more than that which can reduce the RF signal and cause a deterioration of power and performance of RFID reader.”

Can't Live Without It
With different RFID technologies in place, companies and businesses can effectively track and manage goods and automate processes that were once handled by human labor. In the process, huge amounts of cost are saved. With growth set to continue, RFID will become a more prominent part of our daily life.

Comparison of RFID of Different Frequencies