In this technological world, companies have many tools that help them work better and succeed. But when it comes to picking the right technology that is effective and friendly to the budget, it can be a bit tricky. One of these technologies is RFID or radio frequency identification.
You may not realize this, but RFID tags are all around us. You will find them in everyday things such as retail labels, employee badges, inventory monitoring systems, payment terminals, and even animal identification.
Choosing the correct wireless tracking technology can be a surprising task because there are many other tools that show elegant characteristics. Well, when it comes to choosing between RFID tags, it is important to understand the difference between active and passive RFID tags.
Active tags are high-energy heroes of the RFID world. They come with their own source of energy, usually a battery, and have a built-in transmitter, like a small radio. The good thing about these tags is that they don’t need an RFID reader to do their job. They can all work alone.
These tags often have smarter computer chips that can do additional items in data. They use the battery to consume their computer chip and the transmitter. Active tags don’t just sit around; they can be programmed to send their data to set hours, at special times, or when something special happens.
The best part? They can talk with an RFID reader from a good distance, such as 300 to 750 feet. The exact range depends on the battery and the type of transmitter they have. Sometimes, active tags also have -onboard sensors connected to them. With their additional intellectual capacity, you can collect data from these sensors, process them, and then send them out.
Active tags are the stars of real-time location systems (RTL), which will help monitor things in real time. These tags can also chat with other active labels without needing an RFID reader. However, they do not communicate with passive or semi-passive tags.
To save energy, they can nap (sleep mode) and only wake up when they get a special signal. In this way, the battery lasts longer. Some active tags even work at two different radio frequencies. At the lowest frequency, they listen and look forward to a signal. When they listened, they woke up and began to speak at a higher frequency, covering a greater distance. It is useful in bigger areas such as container yards.
Active tags can do great tricks like sending a signal to say: “I’m here,” or even shouting, “low battery,” when they need a battery change. The U.S. Department of Defense has been using these tags for a while.
Active RFID systems require three main things: a reader, an active tag, and an antenna. The special thing about active tags is that they have their long-lasting battery. This battery allows them to continue sending signals and sharing data stored on the label.
Active tags usually work at very high frequencies, somewhere between 433mHz and 960mHz. This means they can send data very far, up to 150 meters away. That’s why an RFID tag is ideal for things like:
- Vehicle tolling: Like when you pay tolls on the road.
- Real-time Location Monitoring: Knowing where things are right now.
- Inventory Management: Keep track of what’s in stock.
- Management of assets: Keep an eye on important things.
There are also different types of active tags. Some send data all the time (beacon), approximately every 3-5 seconds. Others (transponders) are better and only send data when the reader is close to saving the battery.
- Active tags can remember and store a ton of data. They are like large RFID memory banks.
- They do not demand much power from RFID readers, which is something good for efficiency.
- They can chat with an RFID reader from very far, over 100 feet!
- Active tags add to radio chatter, which can be a bit noisy.
- They can be quite sensitive to rough environmental conditions, not as difficult as passive tags.
- Their batteries will not last too long; they usually last only 2 to 7 years.
- Active tags can be expensive and less economical.
- They are larger and weigh more than other types of tags.
- They can’t do their things themselves without an RFID reader.
Passive tags are like quiet players in the RFID game. They do not have their own source of power; There are no batteries on board. Instead, they obtain their energy from the radio waves sent by the RFID reader. But, this energy is relatively small, just enough to awaken the small computer of the tags.
Because they have little power, passive tags cannot respond back to the RFID reader, which is really good because they do not make too much noise in radio waves. To chat with the reader, passive tags use a technique called inductive coupling for low and high frequencies and radiative coupling for higher frequencies. Inductive ones have a short distance chat, like a few inches in a couple of feet, while radiatives can chat about 20 feet away.
Now, here is the thing: when a passive tag is out of place where the RFID reader sees it (we call it the “interrogation zone”), it really is a nap. It has no power, and it cannot do much. Therefore, it cannot have an elegant sensor like those for the temperature or pressure that requires constant power. It is quite simple and less expensive compared to the most active labels.
In the RFID world, we use passive tags a lot. You will find them in adhesive labels that can easily stick to things, or sometimes they are built right on the items themselves. Because they are cheap, we often use them in areas where we do not need to use the labels again. For example, in a supply chain, a case of stuff can have passive tags on it. But when we empty the case and throw it away, the tags also go with it, which makes sense because they don’t cost much.
In a passive RFID setup, there are three main components: a reader, an antenna, and a passive label. The good thing about passive tags is that they have no battery or energy resources. Instead, they have two parts: an antenna and a small microchip.
Passive tags do not talk at all times like active ones. They just sit quietly until they receive the reader’s signal. When the reader sends radio waves, the label wakes up, thanks to those waves, and sends a signal back. This is called “backscatter.”
Like active tags, there are different types of passive RFID tags, too. Two common types are inlays and hard tags. The inlays are simple and inexpensive; They often stick to things with adhesive. Passive hard labels are sturdy and are made of materials such as plastic and metal. They are great for things that go through poor conditions, such as:
- High temperatures
- Bad weather
- External areas
And, like active tags, passive RFID tags also use different radio frequencies. Each frequency has its own scope of reading, ways to attach them, and what they can do.
- Passive tags are small and do not have much weight. They don’t bulk up with which they get attached.
- They are not expensive, especially when you buy a lot of them.
- They do not disturb the waves. There is no excessive radio noise.
- They can last more than 20 years, so they are quite durable.
- They can handle rough conditions without giving up.
- They depend on an RFID reader to wake them up and start their work. They cannot work alone.
- They cannot store much information. They are like the minimalists of the world of RFID.
- They need an RFID reader that can pump more energy.
- They can only talk to the reader from a few inches 20 feet away.
- Whether this short-distance chat is good or bad depends on what they are used for. For things like credit cards or accessing cards, a short range is good because you don’t want someone to snoop on your card from away. But in a supply chain where they tag big pallets, a short range can be a problem because the forklifts need to get closer to the reader.
The huge difference between the active tags and passive RFID tags comes down to the batteries. Active tags have them, while passive tags don’t.
Active tags can chat with the RFID reader from longer distances, but here’s the kick: Passive tags are a popular choice because they are cheaper and offer a lot of options, thanks to their widely accepted standards. In addition, they cost less to work, as they do not need battery changes.
In most cases, having a shorter reading range is an advantage. Why? This means that you can be sure that the labeling is in front of you or the reader. This is very useful -especially when you have to do a quick check of lots of tagged items with a handheld RFID reader.
Thus, when it comes to choosing between active and passive RFID labels, cost and convenience often make passive tags win. They may have a shorter reach, but they do the job without breaking the bank.