Radiofrequency technology is common in our lives. Most people probably use RFID weekly or daily, but how much do you know about RFID? To better protect our money and identity, we need to understand the types of RFID tags and their applications.
What are the Most Common of RFID Tag Types We Use?
There are a variety of RFID tags on the market, and their frequency range generally distinguishes them. RFID tag types can be classified as low-frequency, high-frequency, and ultra-high-frequency. RFID cards typically use one of these three frequencies to communicate via radio waves. Almost every RFID type we can see can be active (powered), passive (un-powered), or semi-passive (battery-assisted).
Regarding tracking assets, you have three options: active, passive, and semi-passive RFID tags.
Active RFID tags are equipped with a battery that periodically transmits signals, which makes them ideal for location-tracking applications. Because the battery boosts signal strength, active tags can reach read ranges up to 100 meters.
Passive RFID tags don’t have a battery and rely on the signal from an external reader to power them up so they can transmit information back to it. Because passive tags don’t have their power source, their read range is typically only one meter or less.
Semi-passive RFID tags combine the best of both worlds: they’re powered by an external source but can also store data for later transmission without recharging by that same source. Semi-passive tags can also maintain their charge for longer than passive ones—typically up to 10 years.
RFID Tag Types – Low Frequency
Low-frequency RFID is a popular type of RFID. It has a band between 30KHz-300KHz and a wavelength of about 2,400 meters.
Low-frequency RFID systems generally only allow communication in a small range between 125KHz-134KHz. It is because multiple types of signals exist between 30KHz-300KHz. Its unique communication channel allows it to penetrate metal and water easily. It is extremely friendly to metal and liquid environments.
Low-frequency RFID has a short read range, even though it has a relatively long wavelength. It has a much shorter read range than HF and UHF, reaching only up to about 50 cm under ideal conditions. It relies on inductive coupling.
Low-frequency RFID tags can be relatively expensive. Different types and applications can lead to price differentiation. The price per tag typically ranges from $0.70 to $20. Since they are powered by inductive coupling, they can last indefinitely. However, because different applications cause different levels of wear and tear, the lifetime can vary. All low-frequency RFID tags use the same type of magnetic coupler for communication, but they can still be made in various shapes and sizes.
It takes longer for the reader to receive and decode the signal from the tag. Because its read rate is slow, the data rate transmitted will also be relatively lower.
Different applications choose different LF antenna or reader combinations. They need to spend from a few hundred dollars to a thousand dollars in cost. The obvious difference between it and other RFID tags is that LF tags do not have security standards. Thus, it is recommended that companies do not use it for applications that require encrypted communications.
LF RFID Application Example
Applying RFID to cows is a durable and effective method of tracking. Tracking is achieved by attaching an ear tag or foot ring with an RFID tag to the cow. People can trace all the links between birth and delivery to market in the RFID tag. In case of contamination, it helps one to recall the exact batch of meat in case of a problem. LF tags are the ideal RFID tag type for livestock tracking applications.
Ear tags with RFID tags have better results than barcodes. They will be more durable and long-lasting. Because livestock may be in the rain, sun, or the presence of other animals for long periods, barcodes are relatively easier to damage. For things that require long-term monitoring, the use of barcodes has yielded suboptimal results.
Low-frequency RFID access control card is one of our common types of RFID tags. It can be used as a key to access control office buildings. These low-frequency RFID access control cards require proximity to the reader to function. It will inevitably cause wear and tear on the access card. If barcodes are used, it is estimated that a new batch of access control cards will need to be replaced in a short time. It is also very easy for criminals to copy access cards made of barcodes, which carry too much insecurity. Access cards made with RFID technology will be more durable and secure.
RFID Tag Types – High Frequency
The high-frequency band on the RF spectrum is between 3MHz and 30MHz. It has a much shorter wavelength – only about 22 meters. Both HF and LF use the same operating principle. The tag and the reader/antenna use magnetic coupling for communication. HF waves allow them to pass through most materials except water and dense metals. For example, HF tags are not affected and work properly in environments with thin metals such as aluminum.
HF RFID systems are diverse, so HF RFID tags produce different read ranges. But in most cases, they have a reading range of a few centimeters to about a meter.
The NFC exists in the high-frequency band of the RFID spectrum. NFC is a global communication standard, and it is regulated internationally. It uses communication protocols approved by the International Organization for Standardization or ISO. Because of its global nature, it makes it easy to adapt NFC to a variety of applications.
Both HF and NFC tags are relatively inexpensive. Depending on the size and shape customized by the company, each tag can cost anywhere from $0.35 to $10. It exists in many forms, usually stickers, cards, or plastic-wrapped labels. It is usually small enough to be used on many items.
NFC tags can be read by the same HF reader or any smartphone with an HF/NFC reader. Since an NFC-enabled smartphone can read it directly, people can use HF/NFC tags in most applications.
HF RFID Application Example
High-frequency RFID technology can effectively improve the efficiency of library checkout and returns. We can use barcodes in conjunction with RFID. The checkout counter’s reader scans the library card’s barcode to get your personal information. The reader detects the RFID tag on the book to obtain text information and quantity. People usually scan their library cards at the register and stack the books on the RFID pad to complete the return record. Afterward, the book is dropped into the designated box to confirm the return of the book. The reader uses the information in the RFID tag to sort the books logically and efficiently.
RFID technology offers a more accurate, efficient, and faster way to get books back on the shelves. It is especially reliable for libraries that want to do more with less. A library needs more work if it uses a barcode system. Staff needs to scan each book separately during the checkout and return process. If the barcode is scratched or marked so it cannot be read, the employee will need to handle it manually. Employees need to enter project information into a computer system. It also causes employees to spend more time doing this.
RFID provides a higher level of security than barcodes. When faced with the number of books checked out, one can scan the barcode on the book to confirm that it has been returned. But what if someone puts down one book and takes the other books that have been confirmed to be returned? RFID readers will immediately identify the discrepancy and let you know.
Managing Medical Supplies
High-frequency RFID can be used to monitor the use of surgical items by patients on the operating table. The check and balance system is beneficial in helping doctors and nurses keep track of the number of sponges used during surgery. It will ensure that no sponge is left inside the patient by the medical staff during the procedure. The reader will count the number of sponges used before and after. If 15 sponges are prepared on the operating table, readers will also check for this after the operation. It ensures the same amount of sponges are taken out of the operating room before and after surgery.
Companies can use high-frequency RFID to monitor the quality of their wines. It is perfect for tracking wine from when it leaves the winery to the distribution center and then to the retailer. Wine needs to be kept in a suitable condition at all times during transportation. Too high or too low a temperature can make it problematic. Companies can program RFID tags. People can use RFID tags to check temperature and other environmental factors affecting wine quality. By reading the tag on the wine, companies can also get a good idea of the environment the wine is in and how long it has been stored. If the data indicates that the wine has been stored in a sub-environment for a long time, it will be treated as damaged goods and removed for destruction. Unlike RFID, barcodes are read-only and cannot actively collect other data. RFID, by contrast, has more functionality.
RFID Tag Types – Ultra-High-Frequency
UHF RFID exists in a broader range of frequency bands than low and high frequencies. It is between 300MHz-3GHz. However, most UHF RFID systems can operate in bands between 860MHz-960MHz. Only a small number of unique RFID systems operate at 433MHz and 2.45GHz.
UHF RFID is not universal. It adheres to the communication protocol standards established by GSI. It is also subject to frequency standards set by individual countries.
The UHF RFID system uses a different communication principle than low and high frequencies. It uses passive backscatter modulation. It is governed by the GS1 EPCglobal UHF Class 1 Generation 2 specification (known as the ISO-18000-6C standard).
The UHF wavelength can be as small as 12 cm at 2.45 GHz. If you look at the average length, it’s about 33cm. We can usually see it in passive RFID systems and active RFID systems.
UHF RFID Application Example
UHF RFID is usually the most common type of RFID tag used in large warehouses and distribution centers. It supports the tracking and identification of multiple items at the same time.
We are more commonly used in shipping and receiving modules. It is especially important for end-to-end manufacturing and industrial asset management. HF RFID differs from the other two RFID types in that it can provide a read range of up to 30 feet under certain conditions. The data transmitted at high-frequency wavelengths will also be relatively faster. It demonstrates that companies can move large quantities of products faster in a short time.
High-frequency RFID technology can reduce the time required to receive pallets or large boxes. RFID readers can be installed at designated platform doors and tuned to the same bandwidth as the tags on the received items. Companies can minimize disruption to their workflow with appropriate adjustments. It provides companies with an efficient and accurate way to move warehouse items through the supply chain.
However, UHF RFID systems are not as mature as those using low and high-frequency RFID frequencies. There is no international standard global bandwidth. The frequency range varies depending on the country/region in which it is used. As far as I know, the US currently uses a higher HF bandwidth than Europe.
Each of the three different RFID tag types has its advantages. Companies must consider various aspects when choosing a tag to find the most suitable RFID type. For example, which type of tag power is appropriate, what protocols a company can use to support these choices, etc.