Radio-frequency identification (RFID) tags are small wireless tags ideal for tracking and identifying objects. They use radio waves to communicate with RFID readers.
RFID technology is increasingly being used in business and consumer applications, making it a critical topic for anyone interested in learning about new technologies. In this blog post, we’ll discuss what RFID tags are, how they work, and some of the applications they’re being used in today. Stay tuned!
What is RFID Technology?
RFID technology is one of many technologies collectively known as automatic identification and data capture (AIDC) technologies. It is a method of remotely storing and retrieving data using electromagnetic fields.
RFID technology has been around for several decades, but it has only recently begun to gain widespread adoption in business and consumer applications. This is due to the declining cost of RFID tags and readers, and the development of new applications that take advantage of the technology’s unique capabilities.
The increased adoption of RFID technology is also because it offers several advantages over other AIDC technologies, such as barcodes. For example, RFID tags can be read without having to be in the line of sight of the reader, making them more convenient to use.
In addition, RFID tags can store more information than barcodes, and they can be read more quickly. Because of these advantages, RFID technology is being used in diverse applications today.
How RFID Technology Works
RFID requires a comprehensive system that includes three main components:
- An RFID Tag. RFID Tags are a small, wireless device containing a microchip and an antenna. The microchip stores information about the tagged object, while the antenna allows the tag to communicate with an RFID reader.
- An RFID Reader. This is a device that uses radio waves to communicate with RFID tags. The reader typically contains an antenna and a decoder.
- A Host System. This is the computer or other device that stores the information read by the RFID reader.
When an RFID tag is brought within range of an RFID reader, the reader emits a radio signal that activates the tag. The tag then responds by transmitting its stored information to the reader. This information is passed on to the host system.
Here, we focus on the first component of the RFID system, the RFID tag. We’ll discuss the different types of RFID tags, how they work, and some of the applications they’re used in today.
What is an RFID Tag?
An RFID tag is a small, wireless device with the following components:
- An RFID Chip
This is the most centrally important component of the tag. It is a microchip that stores information about the tagged object. The chip can store up to 2 KB of data, typically used to identify the object it is attached to.
The RFID chip is powered by the electromagnetic field emitted by the RFID reader. When the tag is activated, it draws power from the field and uses it to transmit its stored information to the reader.
- An Antenna
The antenna is used to receive signals from the RFID reader and transmit signals back to the reader. The antenna is made of copper or aluminum wire, and it can be either a printed circuit or a coil antenna.
The location of the antenna on the tag determines the range at which the tag can be read. Tags with a printed circuit antenna are typically smaller and have a shorter read range, while tags with a coil antenna are larger and have a longer read range.
- A Protective Covering
This is a durable material that protects the RFID chip and antenna from damage. The type of material used depends on the intended use of the tag.
For example, tags that will be exposed to harsh environments (such as extreme temperatures or chemicals) need to be made from materials that can withstand these conditions, such as Epoxy. The type of protective covering affects the size and shape of the tag.
How Do RFID Tags Work?
RFID tags store information about the tagged object on an RFID chip. The reader emits a radio signal that activates the tag, and the tag responds by transmitting its stored information to the reader.
The tag can be read at any time, as long as it is within range of the reader. This makes RFID tags much more convenient to use than other AIDC technologies, such as barcodes.
RFID tags are classified into:
- Passive RFID Tags
- Active RFID Tags
- Semi-Passive RFID Tags
Let’s take a closer look at each type of tag.
- Passive RFID Tags
Passive RFID tags are the most common type of tag. They are powered by the electromagnetic field emitted by the RFID reader, and they use that power to transmit their stored information to the reader.
Passive RFID tags are typically much smaller than active RFID tags, and they have a shorter read range. However, they are also much less expensive to produce, which makes them the preferred choice for most applications.
- Active RFID Tags
Active RFID tags are powered by a battery, which gives them a much longer read range than passive RFID tags. They can also store more information than passive RFID tags and can be equipped with sensors that measure things like temperature or humidity.
However, active RFID tags are also much more expensive, which limits their use to applications where the extra features they offer are needed.
- Semi-Passive RFID Tags
Semi-passive RFID tags has both passive & active elements (hybrid). They are powered by a battery, which gives them a longer read range than passive RFID tags. However, they only use that power to transmit their stored information when activated by the RFID reader.
This makes them more energy-efficient than active RFID tags, and it also makes them less expensive to produce. Semi-passive RFID tags are used in applications where longer read ranges are needed but the extra features offered by active RFID tags are not.
Types of RFID Tags (Based on Frequency)
RFID tags can be classified into different categories based on the frequency of the signal they use to communicate with the RFID reader. The three main frequencies are LF, HF, and UHF.
However, there are also Microwave RFID tags, primarily used for vehicle identification (Real Time Location Systems), and Passive Optical Network (PON) tags, used in fiber-optic networks.
- Low-Frequency (LF) RFID Tags
LF RFID tags operate at frequencies between 30 kHz and 300 kHz. However, only 125 kHz and 134.2 kHz are widely used. LF RFID tags typically have a shorter read range than HF or UHF RFID tags.
These tags use near-field coupling, which means that the reader and the tag must be close to each other (usually less than 10 cm) for the tag to be read. Here are the main characteristics of LF tags:
- Passive. Most LF tags are passive, which means they have no battery. They rely on the electromagnetic field emitted by the RFID reader to power their circuits.
- Short Read Range. The read range of LF tags is typically only a few centimeters.
- Low Cost. The low cost of LF tags makes them the preferred choice for many applications, such as access control and animal identification.
- Lots of Regulations. Some common standards for LF RFID tags are ISO 11784/85 (FDX-B), ISO 14223 (HDX), Animal Identification Devices Interference Regulations, and International Electrotechnical Commission (IEC) 18000-2.
- Limited/No Anti-Collision Capabilities. These tags are prone to collisions (when multiple tags are read simultaneously). This limits their use in applications where lots of tags need to be read at once.
- Expensive to Manufacture. The manufacturing process for LF RFID tags is more expensive than for HF or UHF tags. They are also thicker and less flexible, making them more difficult to use in some applications.
- Less Susceptible to Interference. LF tags are less susceptible to interference, which makes them a good choice for applications where RFID will be used near other electronic devices.
- Ideal for Animal Identification & Tracking. These tags are often used for animal identification because they work well on water-containing objects like skin. Their efficiency is not affected by liquid or metal.
The LF RFID tags are used for many different applications, including animal identification, access control, and identification of industrial tools. They are the most commonly used RFID tags.
- HF RFID Tags
HF RFID tags operate at frequencies between 3 MHz and 30 MHz. The most common HF RFID frequency is 13.56 MHz, used in standards such as ISO 15693 and 14443. HF tags typically have a longer read range than LF tags but a shorter read range than UHF tags.
HF RFID tags use inductive coupling, which means that the reader and the tag must be close to each other (usually less than 1 meter) for the tag to be read. Here are the main characteristics of HF tags:
- Mostly Passive. Most HF RFID tags are passive, meaning they don’t have a battery. They rely on the electromagnetic field emitted by the RFID reader to power their circuits.
- Short to Medium Read Range. The read range of HF tags is typically between 10 cm and 1 meter. This limited read range is due to the inductive coupling technology used by HF tags.
- Anti-Collision Capabilities. HF tags often have anti-collision capabilities. This is very useful in applications where lots of tags need to be read, all at once.
- High Memory Capacity. HF RFID tags have a high memory capacity (up to 4k of data), meaning they can store more data than LF or UHF tags. This is useful in applications where more data needs to be stored on the tag, such as in supply chain management.
- More Susceptible to Interference. HF tags are more susceptible to interference than LF tags, limiting their use in some environments. However, you can still use them in applications where RFID will be used near other electronic devices.
- Ideal for Metal & Liquid-Containing Objects. You can use HF tags on metal and liquid-containing objects without affecting their performance.
Additionally, NFC falls into the HF category, as it operates at 13.56 MHz. However, NFC has some additional features that differentiate it from other HF RFID tags. For example, NFC tags can only be read by NFC-enabled devices.
HF RFID tags are used for many different applications, including supply chain management, access control, and contactless payments. They are faster and can read multiple tags at once, making them more efficient than LF RFID tags.
- UHF RFID Tags
UHF RFID tags operate at frequencies between 300 MHz and 1 GHz. The most common UHF frequencies are 433 MHz, 860 MHz, and 960 MHz. UHF tags have the longest read range of all RFID tags. Here are some of its features:
- Passive/ Active/Battery-Assisted. These tags can be either passive, active, or battery-assisted. Passive tags rely on the reader’s electromagnetic field to power their circuits, while active tags have a battery that powers the tag’s circuits. Battery-assisted tags have a very small battery that is used only when the tag is read, which extends its read range.
- Long Read Range. The read range of UHF tags is up to 50 feet. It is the longest read range of all RFID tags, making it a good choice for long-distance applications.
- Anti-Collision Capabilities. UHF tags often have anti-collision capabilities, allowing you to read multiple tags at the same time.
- Fast Read Speed. UHF RFID tags have a fast read speed, making them a good choice for high-speed applications.
- Low Cost. These are the most affordable RFID tags, making them a good choice for applications where cost is a concern.
- Do Not Work Well on Metal & Liquid-Containing Objects. UHF tags cannot be used on metal or liquids, as they will interfere with the tag’s performance. However, some have been modified to work in these environments.
UHF RFID tags are used for many different applications, such as inventory management, supply chain management, and asset tracking. They are more affordable than HF tags and have a longer read range, making them a good choice for many different applications.
- Microwave RFID Systems
Microwave RFID systems operate at 2.45 GHz and 5.8 GHz. They have a very long read range and can be used in all environments, including on metal and liquid-containing objects. Here are some of their features:
- Passive/ Active/Battery-Assisted. Most microwave RFID tags are active, meaning they have a battery that powers the tag’s circuits. However, some passive tags rely on the reader’s electromagnetic field to power their circuits.
- Long Read Range. The read range of microwave RFID tags can be up to 300 feet. It is the longest read range of all RFID tags.
- Quite Expensive. Microwave RFID tags are more expensive than other types of RFID tags. They are also more demanding/ time consuming to manufacture.
- Work Well in Any Environment. The tags can be used in any environment, including on metal and liquids.
Microwave RFID tags are mostly used for long-distance applications, such as asset tracking. They can be used in any environment and have a very long read range. However, they are quite expensive.
How Are RFID Tags Used?
RFID tags are used in a wide variety of applications, including inventory management, asset tracking, and security.
- Inventory Management. RFID tags are used in inventory management. They help to track inventory levels and locations. This information is critical in optimizing the supply chain and reducing losses.
- Asset Tracking. RFID tags track the location of assets, such as equipment, tools, and vehicles. You can use this data to optimize maintenance schedules and improve asset utilization.
- Security. RFID tags are used to track people and belongings. This prevents theft and loss. They are also used to control admission. This way, only authorized individuals can access a premise. This is also critical in high-security zones. Employers use RFID tags to restrict access to such places.
- Animal Tracking. Low frequency RFID tags are used to identify and track animals at home or zoos. Home owners can also use them to monitor the well-being of their pets. We recommend that you strictly use LF tags for this function since their functionality is not affected by blood/ animal tissues.
There are many different types of RFID tags, each with its own set of features. The type of tag you choose will depend on your application.
If you need a long read range, you should choose a UHF or microwave RFID tag. However, microwave RFID tags are quite expensive.
If you need a tag that can be used in all environments, including on metals and liquids, you should choose RFID anti-metal tags or RFID liquid-resistant tags.
If cost is a concern, you should choose a UHF RFID tag. These tags are the most affordable but do not work well on metal or liquids. It is up to you to choose the RFID tag that best suits your needs. You can also refer to the custom RFID tags guide
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