RFID is definitely making its mark in the technology world and as the number of possible applications multiplies, it becomes increasingly important people understand what it is and how it works. The main problem with that is, RFID can be confusing, and with all of the terminology it might feel like you have to learn a whole new language to understand it.
Here at Computype, we work with customers to create a variety of RFID applications. Over the years we have gained a great amount of knowledge and expertise that we want to share. Whether you are looking to revamp your company’s production process, or just want to know how your contactless credit card works, we hope our RFID glossary can help you decipher the answers to your questions.
Like all tags, active tags have an integrated circuit and antenna, however, unlike passive tags they also have an onboard transmitter and battery. In addition the battery can power additional features such as integrated sensors, longer read ranges and a higher data capacity. Active tags tend to be relatively large in size due to the inclusion of these additional parts and the more features they have, the shorter their battery life.
When it comes to RFID, the word antenna can mean one of two things.
This first is the antenna within the tag. Its job is to transmit data stored in the chip to the reader. When looking at an RFID tag, you will see silver or copper coloured lines coiled around the outer edge of the tag and spiraling towards a spot near the middle, this is the antenna.
The second RFID definition of antenna refers to the antenna within the reader. This antenna sends radio waves to the tag in order to activate it. Another name for this type of antenna is the scanning antenna.
The chip is the component of an RFID tag where data is stored. The chip is connected to the antenna allowing the information stored in the chip to be picked up by a reader.
A concentrator is a device which connects to several RFID readers and gathers data from them. Concentrators typically filter out information deemed unimportant and transfer the important information to a host computer.
Coupling is the method used to link a reader to a tag, so the tag can be recognised by the reader and information can be retrieved. There are two types of coupling:
Inductive coupling is also known as magnetic coupling and happens when the reader and tag are within read range of one another. Once they are within range, the reader creates a magnetic field and transfers electricity through the antenna of the tag, powering the tag and allowing the data to be transferred.
Radiative coupling, sometimes called backscatter, begins when the reader radiates electromagnetic waves. If a tag is within range of the reader it will capture the waves and reflect them back to the reader. Tags which use radiative coupling typically allow for very large read ranges and often require active RFID tags (tags with batteries).
Data transfer rate
The data transfer rate refers to the number of characters able to be transferred from an RFID tag to a reader within a specified period of time.
Electromagnetic interference (EMI)
This occurs when radio waves coming from one device distort waves coming from another. Wireless internet connections, cellular connections and even some automation devices can have a negative effect on the readability of RFID tags.
Tags located further than one wavelength from the reader are considered to be in the far field. Ultra-high frequency tags rely on communicating in the far field allowing them to have a longer read range than low and high frequency tags.
The frequency is the number of cycles a wave, such as a radio wave, completes in a single second. It is generally measured in hertz, most often kilohertz or megahertz. A wave that completes one cycle in one second would have one hertz. The journey from the midpoint of one wave to the midpoint of the next is considered to be one cycle. RFID is available in three levels of frequency:
Low Frequency (LF) RFID
Tags that operate at 125–134 kilohertz are generally considered to be low frequency. Low frequency tags tend to have slower data transfer rates and can only be read from close range. Read ranges for low frequency tend to be measured in centimeters and inches. Low frequency tags also have the unique ability to transmit data through RFID opaque materials.
High Frequency (HF) RFID
High Frequency tags always operate at 13.56 megahertz. These tags are used in a wide variety of applications due to their fast data transfer rates and range of storing capacities and read distances. High frequency tags also hold the ability to operate near RFID opaque materials.
Ultra-High Frequency (UHF) RFID
Most ultra-high frequency systems operate between 860 and 960 megahertz. These tags are often used in situations where items need to be tracked from a distance since the read range for UHF is typically measured in feet and meters. They are also known for their extremely fast data transfer rates. Unlike low and high frequency tags, ultra-high frequency tags have a very low tolerance to RFID opaque materials.
The inlay is the RFID portion of an RFID label, it includes the chip and antenna mounted onto a substrate.
Simply another term for the chip, the component of the RFID tag where data is stored.
Devices which have been added to the RFID tag in order to detect and record environmental disturbances such as changes in temperature, lighting and loud noises.
Another term for reader or scanner, the part of an RFID system which reads a tag or transponder.
The acronym for Internet of Things. The Internet of Things is a vision for the future entailing anything running on electricity would be connected to the internet. In this theoretical future people will not only be able to interact with other people, but with things as well and things will be able to interact with other things.
NFC stands for Near Field Communication, which is a technology that allows smart phones to interact with readers via RFID. NFC allows smart phone users to do things such as make payments and redeem coupons by waving their phone within a couple of inches from a reader.
An onboard battery is attached to a tag and used as a power source. These are required for semi-passive and active RFID tags since they either use radiative coupling or have additional features that require them to run without the presence of a reader.
A transmitter used in active tags to transmit the signal from the reader rather than reflect it back to the reader. This provides active tags with longer read distances.
Passive tags do not require an onboard battery, instead they receive power from the reader during the inductive coupling process. In addition to not having a battery, these tags do not have any additional data storage meaning they have a lower memory capacity than semi-passive and active tags. The lack of additional features does, however, improve the life span of the tag.
Reading is what occurs as a result of coupling. Once a tag and reader have coupled, the reader obtains and translates the data stored in the tag.
A reader is a piece of equipment consisting of two major parts, the scanning antenna and the receiver. The reader activates the tag and obtains and translates the information stored in the tag to a human readable form.
The maximum distance from a reader that a tag remains readable.
The number of tags a reader is able to read within a specified time period is the read rate.
This term describes tags that are able to be rewritten to store new information. These tags can be applied in many ways and are often found on reusable containers or items being tracked along a process.
The part of a reader that receives the information transmitted by the tag.
RFID stands for Radio Frequency Identification, which, as the name would suggest is a form of identification using radio waves. The equipment involved in RFID is a tag and a reader. The reader couples with the tag and retrieves data stored in the chip through an antenna in the form of radio waves.
RF–lucent refers to a material radio waves are capable of traveling through.
RF-opaque refers to a material radio waves are unable to travel through. These include liquids and metals.
RTLS is the acronym for Real Time Location System. These systems use RFID to track the locations of people and objects in real time.
Scanner is another term used to describe a reader or interrogator, the equipment used to receive and translate information stored in a tag.
The antenna on the reader that sends radio waves to the tag in order to activate the tag.
Semi-passive tags typically do not house an onboard transmitter, but do use a battery to power the integrated circuit and receiver. These tags are also capable of including additional features such as the ability to record sensed data.
Barcode labels that contain RFID inlays are called smart labels. They can serve as a backup form of identification in case the barcode becomes unreadable, and in some cases store additional information unable to be stored in a barcode.
An RFID tag is made up of a microchip and an antenna. The microchip stores information, usually about the object the tag is attached to and is capable of transmitting that data through the antenna in the presence of a reader.
Another term for tag. The part of an RFID system which is read by the reader. A transponder is made up of two main parts, a chip and an antenna.
An acronym for the phrase “write once, read many” referring to a tag that can be written only once, and only read from that point on. These tags are also known as read only tags.
The amount of time in which information can be transferred to a tag, stored in its memory and confirmed to be correct is referred to as the write rate.
It’s really only the beginning for RFID. As the Internet of Things gradually becomes a reality it will play a major role in everyone’s daily lives. Because of the important role this world changing technology is expected to play it’s becoming especially important that everyone understand it. Hopefully this glossary helps you to better understand the terminology associated with RFID so you can research confidently and if you want to put your newfound knowledge to the test, check out the rest of our RFID blogs!