RFID and Smart Labels

RFID (Radio Frequency Identification) is a complementary technology to bar codes that uses radio-frequency tags to carry data about the items to which they are attached, with Smart Labels combining RFID with conventional printed barcodes on a single label.

What is RFID?

RFID stands for radio frequency identification. It is a complementary technology to bar codes. RF tags, or "transponders" (from TRANsmit-reSPOND), carry data about the items to which they are attached. RFID technology is applied in livestock farming (to trace the history of each animal), car manufacturing (build history of each vehicle), and freight (shipping manifests), to name a few applications.

RF Tags — There are two general types: passive and active. Active tags have a built-in power cell and a higher communication range, but a life limited to that of the power cell. Passive tags carry no on-board power, deriving it instead from the reader; this gives them a practically unlimited life but a shorter range.

For most general applications, passive tags are usually the most cost-effective choice. They are made in a wide variety of sizes and materials: durable plastic tags for discouraging retail theft, wafer-thin tags for use within "smart" paper labels, tiny tracking tags inserted beneath an animal's skin, and credit-card-sized tags for access control. In most cases the data storage on a passive tag is fairly limited — capacity is often measured in bits rather than bytes. However, most applications only need a relatively small amount of data codified and stored on the tag, so the limited capacity is rarely a major constraint. Most tags also carry an unalterable, unique electronic serial number, which makes RFID tags valuable in applications where item tracking or security is important. Read/write range depends on the tag type, with active tags generally offering a longer range than passive tags; for passive tags, the most critical factor for range is the type and size of the reading antenna.

Frequency ranges — RFID systems operate across three frequency ranges. Low frequency (100 to 500 kHz) is the least expensive and has a low reading rate at short to medium distances; typical uses include vehicle immobilizing, livestock identification, and access control. Intermediate frequency (10 to 15 MHz) offers a medium reading rate at short to medium distances and is ideal for smart cards. High frequency (850 to 950 MHz, 2.4 to 5.8 GHz) has the fastest reading rate and long-range capability, but requires a line of sight between reader and tag and is the most costly option; a typical application is automated toll collection.

Reading and Writing Tags — RF tag readers range from desktop devices to handheld computers capable of writing data to tags as well as reading them. The choice of reader depends on the application — for example, whether it will be used in a fixed position or needs to be portable.

Consideration must also be given to the type of tags used. There are many manufacturers of RF tags, and compliance between manufacturers has historically been limited. Efforts are underway to introduce global standards, and greater uniformity is expected in the coming years.

Smart Labels — The term "Smart Labels" refers to super-thin RFID tags embedded into otherwise conventional labels. From an application standpoint, the real benefit of Smart Labels is the ability to combine human-readable printed data with data storage capability, and often barcode-reading capability as well, by printing a conventional barcode on the label. Combining these three forms of readability with RFID "writeability" opens up a range of opportunities for low-cost tracking and traceability. Some thermal transfer label printers now offer the additional capability to write data to a Smart Label at the same time the label is printed.

Putting together systems — RFID is a specialized but rapidly expanding field. Organizations requiring RFID solutions need to work closely with a systems provider that has in-depth knowledge of the technology and can create a complete solution tailored to the customer's needs.