Some people say that RFID can bring huge benefits to businesses, is it true?
To know better you can read this article.
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RFID has several advantages over barcodes, including the ability to read multiple tags simultaneously, the ability to read tags through non-metallic materials, and the ability to read tags that are not in line-of-sight of the reader. And in some cases RFID can replace barcodes as a means of tracking and identifying items (read more about can you replace barcodes with RFID?).
What is RFID
RFID stands for radio frequency identification, that is identifying something with radio waves. Radio waves are a type of electromagnetic waves. Light is also a magnetic field and an electromagnetic wave, but the frequency of light waves is so high that it’s not considered a radio wave.
The “resolution” that can be achieved by visible light is so high that you can see bacteria. And it’s really easy now to have pixel sizes on the screen that are on the edge of what the human eye can see. This is used by barcodes.
The “resolution” for radio waves is so bad, that the smallest “pixel” is about the size of a full sheet of paper! Imagine, if you want to have a picture of a barcode made in radio waves, then you have to cover a full stadium with black and wide full sheets of paper. This is why the information conveyed by RFID is sent via dots in time rather than dots in space, it’s more like a Morse code or music rather than a picture or a movie.
The RFID reader emits radio waves, the RFID tags do something with them, the RFID reader receives radio waves back, something like that.
OK, so that was simple.
Why different RFID standards?
What is not simple is that different radio frequencies are so different that the physical laws prevent having a unified piece of equipment to be used to utilize all of RFID at all frequencies.
So there are different RFID standards. Those standards are not the way different companies competing with each other, as one might thing, but a way to deal with the differences in physics.
Different RFID standards are incompatible, so it's good to know the specific strengths and weaknesses of each. For example, RFID systems used to count cattle operate at low frequencies and cannot read access cards, which use high frequencies. And access card readers cannot read clothing tags.
They even use different principles of communication. Lower-frequency standards tend to use tags that couple with the reader and induce the signal onto the emitted wave (like pulling the strings). Higher-frequency standards tend to backscatter the emitted wave (like hitting back the tennis ball).
Wave frequency highly affects the wave’s ability to penetrate metallic objects, concrete walls and things that are made of water. This also influences the reasonable applications for each standard.
Finally, frequency directly influences the data-rate at which the information can be transferred between the reader and the tag. And because some low-frequencies result in really low rata rates, merely bits a second, this also affects the available applications.
Ultra-High Frequency (UHF) RFID
Most of the tags for logistics and retail are Gen2 RFID, also known as UHF or RAIN RFID. Gen2 operates at ultra-high frequencies, allowing it to count hundreds of tags at a distance of several feet. However, the same frequency also prevents it from penetrating water or metal, making it difficult to read groceries, equipment, or people at speed.
As a result, Gen2 is used for speed counting in textile products and footwear, while it's used mostly for robust identification in spare parts and equipment.
Gen2 uses several techniques, such as wireless charging, walkie-talkie communication, and GS1 barcode data, to uniquely identify the objects of interest.
Most RFID tags are simply chips with an antenna and a tiny battery, so the reader first wirelessly charges the tags in a split second. The battery lasts for a minute or less, so the reader then starts talking to the tags using walkie-talkie communication. Each tag tells the reader the ID of the object it's attached to, and the whole process takes just one-tenth of a second.
Now, you may be starting to see the potential and limitations of Gen2 RFID.
First, you have to be within a reasonable range to charge the tags, several feet rather than hundreds of feet.
Second, the reader and each tag must communicate separately, without clogging the airwaves, so too many tags can cause problems.
And third, because it's a walkie-talkie, not a visual sign, you never know exactly where the tag is - it could be ten feet away, around the corner, or right behind you.
But on the other hand, you can talk to hundreds of tags at once, and they will all report to you one by one in just one-tenth of a second. That's why there are literally billions of items tagged with Gen2 RFID all around us.
Recent poll shows that most people think of RFID as of an expensive technology for expensive clothing, where in fact it's mostly used by cheap clothing brands (River Island, Centerpoint, H&M, etc.).
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Why is that?
It's because RFID really optimizes operations, which is especially valuable if you are operating huge volumes of low margin products.
In contrast, high-cost brands have few items and a ton of margin to cover all inefficiencies, no need for optimizations.
Why is there no RFID in groceries? Mostly because of water and metal that block the radio waves.
High Frequency (HF) RFID
HF RFID tags are bank plastic, nol cards, pass-cards, etc., so there are plenty of them all around.
High-Frequency RFID (HF RFID) operates at a frequency range of 13.56 MHz, that is almost 100 times lesser than UHF (hence, the speed is at least 100 times slower).
There are several disadvantages of HF RFID compared to UHF RFID:
The pros and cons of HF RFID both come from the same issue: limited range. HF RFID has a very short read range, typically 8-10 cm. This limits its use in applications where a longer read range is needed, but it’s a benefit when you want some security.
Overall, UHF RFID is generally more suitable for large-scale applications such as supply chain management and asset tracking due to its longer range, faster data rate, and greater durability. HF RFID is more suitable for applications where close proximity is required and where cost is a factor, such as access control and ticketing.
Low Frequency (LF) RFID
Actually, LF is the least interesting RFID standard for retail and logistics, because of its low speeds rates and low-memory tags, with just a few bytes being sent in a second from a single tag.
Low frequency (LF) RFID operates at much lower frequencies than UHF, typically between 30 kHz and 300 kHz. This means lower energies and hence much shorter ranges than Gen2 RFID, typically only a few inches.
One real example of low-frequency RFID in use is animal identification. LF RFID tags implanted in animals can be read at a distance of several inches, allowing for easy tracking and identification of individual animals. This is especially useful in the livestock industry, where it is important to keep track of the health and well-being of each animal, to automatically open gates, food pipes, etc.
LF seems attractive when you see a desktop USB LF reader for just a few bucks, compared to hundreds and thousands of bucks for UHF. But this attraction quickly dissolves when it comes to tags, for LF tags being sometimes 10 times more expensive than UHF, because of too much metal used.
The only reasonable use of LF RFID in logistics is tracking metal objects such as carts and wagons, due to its ability to penetrate metal and water to a limited extent.
Overall, while LF RFID has its uses, it is not as well-suited for retail and supply chain management as other RFID standards.
EAS (Not a RFID)
Now let's take a look at EAS technology that is radio waves but NOT RFID, because it identifies nothing, so not to mismatch them.
EAS (Electronic Article Surveillance) is a security system used to prevent shoplifting in retail stores. It works by using sensors to detect the presence of an EAS tag or label on an item of merchandise. If an item with an EAS tag or label, without being deactivated or removed, passes through the security gates, an alarm sounds.
EAS does not identify anything by itself. It only detects the presence of an EAS tag. The EAS tag does not contain any information or identification. It only acts as a trigger for the EAS system to alert store personnel.
On the other hand, RFID (Radio-Frequency Identification) is a technology that uses radio waves to communicate between a tag and a reader. "Communicate" means "exchange data". RFID tags can be attached to objects and are used to store and transmit information wirelessly.
The only "information" that EAS tag is transmitting is that it is here, and it wasn't deactivated.
EAS and RFID are two different incompatible technologies that are used for different purposes. EAS is primarily used for security and loss prevention, while RFID is used for a wide range of applications including inventory management, supply chain tracking, and access control.
Although, there are combined tags available on the market, that are just EAS & RFID tags glued together.
