Credit: Adrian Sulyok
RFID Technology Types
Radio frequency identification (RFID) technology has become much more common across a number of industries, but there are a variety of different types of RFID technology
, tags, and readers — each uniquely suited to different types of applications. RFID tags can be classified by the radio frequency range they use to communicate (low, high, or ultra-high), and the way the tag communicates with the reader (active or passive). Listed below are the different types of RFID technology, their capabilities and limitations, and the types of applications for which they are best suited. RFID is regulated by ISO 18000-63 which is promoted by the RAIN RFID Alliance
. Standards are industry specific and are regulated or standardized at the national, regional, and global levels. This ensures that RFID tags work with any reader and do not interfere with each other.
What’s the Frequency?
RFID tags can be grouped into three categories based on the range of frequencies they use to communicate data: low frequency (LF), high frequency (HF) and ultra-high frequency (UHF). Generally speaking, the lower the frequency of the RFID system, the shorter the read range and slower the data read rate.
Credit: Nana Smirnova
Low Frequency (LF) RFID:
These RFID systems operate in the 30 KHz to 300 KHz range, and have a read range of up to 10 cm. While they have a shorter read range and slower data read rate than other technologies, they perform better in the presence of metal or liquids (which can interfere with other types of RFID tag transmissions). Common standards for LF RFID include ISO 14223 and ISO/IEC 18000-2. LF tags are used in access control, livestock tracking, and other applications where a short read range is acceptable.
High Frequency (HF) RFID
HF systems operate in the 3 MHz to 30 MHz range and provide reading distances of 10 cm to 1 m. Common applications include electronic ticketing and payment and data transfer. Near Field Communication (NFC) technology is based on HF RFID and has been used for payment cards and hotel key card applications. Other types of smart card and proximity card payment and security systems also use HF technology. Standards include ISO 15693, ECMA-340, ISO/IEC 18092 (for NFC), ISO/IEC 14443A and ISO/IEC 14443 (for MIFARE and other smart card solutions).
Ultra-High Frequency (UHF) RFID
These systems have a frequency range between 300 MHz and 3 GHz, offer read ranges up to 12 m, and have faster data transfer rates. They are more sensitive to interference from metals, liquids, and electromagnetic signals, but new design innovations have helped mitigate some of these problems. UHF tags are much cheaper to manufacture, and as such are commonly used in retail inventory tracking, pharmaceutical anti-counterfeiting, and other applications where large volumes of tags are required. The EPCglobal Gen2/ISO 18000-6C standard is a well-known global standard for item-level tracking applications. Check out real-world examples of UHF RFID applications and ROI with our case study on Returnable Container tracking
or our white paper “Returnable Container Tracking: Challenges, Benefits and Financial Impact.”
Passive or Active?
There are two other common classifications of tags, depending on how the tag communicates with the reader: passive or active.
Active RFID tags have their own transmitter and power source (usually a battery) onboard the tag. These are mostly UHF solutions, and read ranges can extend up to 100 m in some instances. Active tags are usually larger and more expensive than their passive counterparts and are used to track large assets (like cargo containers, vehicles, and machines). Active RFID tags are also often equipped with sensors that measure and transmit temperature, humidity, light, and shock/vibration data for the objects they are attached to. There are two types of active tags. Transponders
only “wake up” and transmit data when they receive a radio signal from a reader. For example, a transponder attached to a vehicle in a toll payment or checkpoint control location would only be active when passing through a particular gate. This helps conserve battery life. Beacons
, on the other hand, emit a signal at a pre-set interval. This type of active tag is used in real-time location systems (RTLS) for tracking anything from wheelchairs at a hospital to large cargo containers at a shipping dock.
In passive RFID solutions, the reader and reader antenna send a signal to the tag, and that signal is used to power on the tag and reflect energy back to the reader. There are passive LF, HF, and UHF systems. Read ranges are shorter than with active tags and are limited by the power of the radio signal reflected back to the reader (commonly referred to as tag backscatter). Passive tags are usually smaller, less expensive, and more flexible than active tags. This means they can be attached or even embedded on a wider variety of objects. Passive UHF tags are commonly used for item-level tracking of consumer goods and pharmaceuticals, for example.
Battery-Assisted Passive (BAP) RFID
A third, hybrid type of RFID tag has also emerged. BAP systems, or semi-passive RFID systems, incorporate a power source into a passive tag configuration. The power source helps ensure that all of the captured energy from the reader can be used to reflect the signal, which improves read distance and data transfer rates. Unlike active RFID transponders, BAP tags do not have their own transmitters.
In addition to frequency bands and power level, RFID tags are made from different materials to suit different purposes. RFID tags can be made from almost any durable material capable of holding an RFID chip. This ranges from various plastics and epoxies to metals, ceramics, Teflon, and proprietary materials. Every application of RFID is unique, and the material should be fit to purpose.
There are several applications that require RFID tags to be heat resistant. Whether it needs to go down an assembly line, into an oil and gas pipe, or through the laundry, an RFID tag can be put in a number of heat resistant and even fireproof materials. Heat resistant RF tags come in standard (up to 450° F), extreme (up to 550° F), and ultra-high (up to 750° F) heat resistance. They can be made out of a variety of materials including nylon, teflon, ceramic, or FR4 as well as proprietary materials. Basically, as long as the RF tag can be contained within the heat resistant material and as long as an RF tag reader can read it, it can be used to house an RFID chip.
In addition to high heat, RF tags sometimes need to come into contact with liquid. Whether it’s water, cleaning chemicals, or bodily fluids, liquids can cause damage to RF tags if not properly protected. For that reason, there are a variety of RFID tag types that are liquid resistant. An additional complication to the material used to hold the RFID chip is the manner in which it is affixed. Many adhesives degrade under exposure to water or chemicals. In addition to liquid resistant adhesives, RFID tags can be sewn into laundry or contained in small, durable boxes.
Credit: National Cancer Institute
There are a variety of applications of RFID systems. The particular RFID technology you choose to use will depend greatly on the industry and application of the RF tag. Here are just some of the applications of RFID technologies.
Assets, Inventory, and Parts Tracking
One of the principal uses of RFID systems is for asset, inventory, and parts tracking. This is because RFID tags can be used to track not just individual items, but also batches. Thus, not only can RFID be used to track items across your enterprise, but also to conduct lightning-fast audits of inventory. RFID tags work with mobile devices that connect to an item tracking software. Many of these software solutions allow integration with your warehouse management system and enterprise resource planning software. With RFID tracking, there’s no more endless searches for missing parts or inventory.
RFID can also be used to manage fleets. With the same mobile devices, you can scan RFID tags affixed to your vehicles. With active RFID tags and GPS, know exactly where all of your vehicles are. In addition to tracking vehicles, you can also use RFID solutions to track what inventory is on which vehicle. This allows shipping tracking for not only you, but also your customers. With data from your RFID system, you can analyze key performance indicators to see where your profit centers and cost sinks are.
Pharmaceutical companies have been adopting RFID technologies to manage recalls and prevent counterfeiting. With each RF tag given a unique identifier, individual bottles and other packages can be tracked across the supply chain from manufacture to the pharmacy. RFID is great for product verification, too. With RFID, you can be sure that pharmacies know that they have drugs from you, the manufacturer, instead of a supplier of dangerous counterfeits. In addition, send out real-time recalls that can be quickly executed across the world.
In addition to pharmaceutical tracking, there are many uses of RF tags in healthcare settings. Hospitals need to have accurate inventories of supplies, and RFID systems make keeping accurate records as simple as the push of a button. RFID is perfect for the medical setting. Because the RF tags can be made from almost anything, there is practically no application they can’t be used for. RF tags can be affixed to gurneys, attached to medical supplies, or even sewn into blankets.
The Right RFID Type for You
By matching the right type of RFID tag to your application, you can ensure a successful deployment and reap the full benefits of the technology. The different types of RFID technology allow you to get creative to solve real-world business problems. Make sure you get the most out of your RFID solution by downloading our whitepaper “Are You Realizing the Full Benefits of RFID?”