What is RFID?

RFID is simply Radio Frequency Identification.

“Radio Frequency Identification is an automatic identification method, relying on storing and remotely retrieving data using devices called tags.”

RFID is similar to bar code technology but uses radio waves to capture data from tags, rather than optically scanning the barcodes on a label. RFID does not require the tag or label to “in line of sight” to read — that's one of the key characteristics of an RFID system.

How does an RFID system work?

For RFID systems to work the following components are essential: -

Tag (Passive, semi passive or active) Reader (also known as an antenna or integrator) Software (also known as middleware)

Information is sent to and read from RFID tags by a reader using radio waves. In passive systems, which are the most common, anRFID reader transmits an energy field that “wakes up” the tag and provides the power for the tag to respond to the reader. In active systems, a battery in the tag is used to boost the effective operating range of the tag and to support additional features over passive tags, such as temperature sensing. Data collected from tags is then passed through communication interfaces (cable or wireless) to host computer systems in the same manner that data scanned from bar code labels is captured and passed to computer systems for interpretation, storage, and action.

What is an RFID Tag?

RFID tags come in many shapes and sizes each suited to a specific application, but all RFID tags can be generally grouped into two main categories, regardless if they are encased, a sticky label or just a solid button like tag.

RFID tags are either “passive” (no battery) or “active” (self-powered by a battery). RFID tags also can be read-only (stored data can be read but not changed), read/write (stored data can be altered or rewritten), or a combination, in which some data is permanently stored while other memory is left accessible for later encoding and updates.

Passive RFID Tags

Passive RFID tags have no internal power supply. An electrical current induced in the antenna by the incoming radio frequency signal provides just enough power for the integrated circuit (IC) in the RFID tag to power up and transmit a response.

RFID tags communicate in various ways with the RFID reader. The aerial (antenna) has to be designed to both collect power from the incoming signal and also to transmit the outbound signal.

Lack of an onboard power supply means that the passive RFID tag can be quite small: commercially available products exist that can be embedded under the skin. As of 2006, the smallest passive RFID tag  measured 0.15 mm × 0.15 mm, and are thinner than a sheet of paper (7.5 micrometers).  

Passive RFID tags have practical read distances ranging from about 10 cm (4 in.) (ISO 14443) up to a few meters (EPC and ISO 18000-6) depending on the chosen radio frequency and antenna design/size.

Due to their simplicity in design they are also suitable for manufacture with a printing process for the antennas. Passive RFID tags do not require batteries and can be much smaller, and have an unlimited life span. Simple laboratory printed polymer tags operating at 13.56 MHz were demonstrated in 2005 by both PolyIC (Germany) and Philips (The Netherlands). If successfully commercialized, polymer tags will be roll printable, like a magazine, and much less expensive than silicon-based tags. The end game for most item level tagging over the next few decades is that RFID tags will be wholly printed - the same way a barcode is today - and be virtually free, like a barcode.

Active RFID Tags

Unlike passive RFID tags, active RFID tags have their own internal power source which is used to power any intergrated circuits that generate the outgoing signal. Active RFID tags are typically much more reliable  than passive tags due to the ability for active tags to conduct a "session" with a reader.

Active RFID tags, due to their onboard power supply, also transmit at higher power levels than passive tags, allowing them to be more effective in "Radio Frequency challenged" environments like water (including humans/cattle, which are mostly water), metal (shipping containers, vehicles), or at longer distances. Many active tags have practical ranges of hundreds of meters, and a battery life of up to 10 years. Some active RFID tags include sensors such as temperature logging which have been used in concrete maturity monitoring or to monitor the temperature of perishable goods. Other sensors that have been married with active RFID include humidity, shock/vibration, light, radiation, temperature and atmospherics like ethylene.

Active tags typically have a much longer range (approximately 300 feet) and larger memories than passive tags, as well as the ability to store additional information sent by the transceiver.

What is an RFID Reader?

An RFID reader is basically a radio frequency (RF) transmitter and receiver, controlled by a microprocessor or digital signal processor (DSP). The RFID reader, using an attached antenna, captures data fromRFID tags, and then passes the data to a computer for processing. As with tags, readers come in a wide range of sizes and offer different features. Readers can be affixed in a stationary position (for example, beside a conveyor belt in a factory or dock doors in a warehouse), portable (integrated into a mobile computer that also might be used for scanning bar codes), or even embedded in electronic equipment such as print-on-demand label printers.

What is RFID Software (middleware)?

So far your RFID system is communicating in radio waves, so software is used to decipher the radio waves into logical terms.

This software can either be separate from your RFID Reader and be stored on a PC or laptop, or it may be integrated into the RFID Reader as with portable devices such as the Datalogic Jet.

This software is like any other piece of software and variations are limitless.

What RFID Frequency should I use?

The RFID frequency you should use for a particular RFID application purly depends on the application and the environment in which the RFID

Low Frequency (LF) - Low Frequency range 70 – 150khz

Animal tracking/husbandry

High Frequency (HF) - High Frequency 13.56MHz

Tote trackng conveying systems

Ultra High Frequency (UHF) - Ultra High Frequency 866Mhz

Logistics supply chain