Active RFID vs. passive RFID

RFID being scanned inside device

Last updated on December 5th, 2023 at 03:31 pm

What is RFID?

Radiofrequency identification, or RFID, is a technology that facilitates the reading and collecting of data via radio waves, as the name suggests. Either an active RFID tag or a passive RFID tag located on the item is read by a reader, sometimes called an interrogator, by way of its antenna. Smart labels may also be used as passive RFID tags. The data is transmitted via radio waves to the reader which then converts this data into a more usable form. Once converted, the data can be read by a host computer system and stored in a database to be accessed at a later time.

RFID is a form of AIDC technology, or Automatic Identification and Data Capture. AIDC allows the user to scan an object so it can be identified and its data can be collected. That data is then stored onto a computer system automatically. Because it uses radio waves, the item being scanned does not need to be in the reader’s line of vision, making inventory collection and tracking easier than with the older barcode technology. RFID can mainly be used in two different forms: active RFID vs. passive RFID. Semi-passive is a third option that uses some aspects of both active and passive.

But we’ll come to that in a moment. Let’s break down all of this technical terminology first:

Readers or “interrogators”:

There are two primary types of readers; active RFID vs. passive RFID readers. In other words, interrogators that interact with passive RFID tags and interrogators that interact with active RFID tags.

When comparing active RFID vs. passive RFID readers, we see that readers that interrogate active RFID tags wait to come into contact with the tag’s signal, which is always being emitted – only then does it read the tag. Active tags have a wider range than passive tags and can even be adjusted to read up to 150 meters away. An excellent example of when this would be applicable is in a toll tag for a car. In places where commuters cross toll roads or bridges, there is often an option to buy an active RFID tag which serves as a monthly toll pass. The driver can bypass the toll booth and continue over the bridge or road quickly. As they pass the toll booth, an RFID reader sends a signal to the tag mounted in the front window of the car. The tag sends back its information to the interrogator letting it know what kind of car it is, who owns it, and that the toll pass has a sufficient balance to cross. If the pass has an account associated with it that has insufficient funds, it can alert the camera system to take a picture of the license plate to add to any applicable records and bill the associated account’s address.

Readers that interrogate passive RFID tags, however, send out a signal to interrogate the passive tag. The passive tag receives this signal from the reader and sends back its identification information. When taking a look again at active RFID vs. passive RFID, passive tags can’t be read from nearly as far as active RFID tags can be, but they are also smaller and less costly to implement. These interrogators typically read passive RFID tags such as employee name badges or wristbands with smart labels printed on them.

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Tags: active RFID tags vs. passive RFID tags

The tags that are used for RFID are what the reader gets a signal from or sends a signal to in order to collect data from the item being presented. As mentioned above, RFID technology comes primarily in two different forms; active RFID vs. passive RFID. There can also be some overlap in what is called semi-passive RFID.

So, what is the difference between active RFID vs. passive RFID tags? Active RFID tags are structured a bit differently from passive RFID tags and are made up of a microchip, an antenna, an internal power supply, and internal technology.

The microchip is where the data about an item is stored. Depending on the context, it may contain information about what the item is or where it is located and holds much more detailed information than a barcode can.

passive radio frequency identification tags

The onboard technology in an active RFID tag can contain many different features, from sensors to input and output ports. Some examples of active RFID tag technology are location detection or heat sensors that can help to keep track of items or personnel location for safety.

The antenna is what the reader uses to collect this information. The shape of the antenna depends on the frequency of the radio waves being transmitted and how far they are traveling. In general, the higher the frequency and the farther the distance, the bigger the antenna will need to be. Active RFID tags require larger antennas than passive RFID tags because they utilize much higher radio wave frequencies and are capable of reading at further distances.

As we analyze active RFID vs. passive RFID tags, it’s not too hard to see how the passive RFID tags are structured slightly differently. A passive RFID tag has an antenna and a microchip much like the active RFID tag does, but when comparing active RFID vs. passive RFID, passive tags do not have the onboard technology or internal power source. What it does have is something called a substrate. This is a material usually made of Mylar or some kind of plastic film that acts as a bonding agent for the microchip and the antenna. It holds the components of a passive RFID tag together. This might manifest as personnel ID badges that are made of a plastic in which the components of the tag are embedded.

Smart labels are a form of passive RFID tag that have a combination of both barcode and RFID technologies. They contain a passive RFID tag inlay, but they can be printed from just about any computer and are used in an adhesive form. They sometimes contain barcodes or other printed information, as well, and are often used on paper products, such as labels for boxes.

Active RFID vs. passive RFID

Now that we know more about the intricacies of active RFID vs. passive RFID we can take a broader look at it. What is the purpose of this technology? Who would benefit from using it and why? Analyzing active RFID vs. passive RFID usage and benefit really just depends on the need that you are trying to meet within your company. Both can be immensely useful and in some cases, something semi-passive might even be the right choice.

Looking at active RFID vs. passive RFID, we see that active RFID tags are very durable and have a wide reading range of up to 150 meters. The higher frequency that the active tag operates on when comparing active RFID vs. passive RFID makes active a better choice when metals or liquids are around as liquids can absorb the signal and metals can reflect it. The best applications for active RFID tags vs. passive RFID tags are usually outdoors and on large assets as the tags themselves are usually quite large. Construction and natural resource collection tend to be good industry candidates for active tags because of the durability and high-frequency radio waves. The downsides to using active RFID vs. passive RFID would be that the cost is usually higher and since the active tags have internal batteries, they will die at some point. Most last somewhere between three and five years, but most also can’t be changed. They also usually require some form of at least semi-permanent mounting such as with rivets, or screws.

Moving on to the passive tag in the active RFID vs. passive RFID discussion, we see that passive tags are much smaller and typically cost less than one dollar per tag. The size variation of assets that they can be attached to is wider, ranging from the very small to the very large and the tag itself is usually quite small. Since they are powered by the radio waves coming from the interrogator, they do not require batteries. Some industries that really benefit from passive RFID technology are healthcare, retail, and manufacturing because the tags are usually small and easily attached to name badges or wrist bands. However, as we are looking at active RFID vs. passive RFID, it should be mentioned that their small size does mean lower frequency. This, in turn, means that they are less effective around water and metal. Their reading range is also typically 15 meters or fewer, which, when comparing active RFID vs. passive RFID, means they can be quite physically limited. The tags are also not very weather resistant. However, seeing as manufacturing, healthcare, and industries like these are usually conducted indoors, these limitations can be easily mitigated. The small size of the passive tags also makes giving tags to patients or employees convenient as they are easily carried around the neck or wrist.

Final thoughts on active RFID vs. passive RFID 

Looking at active RFID vs. passive RFID gives an idea of their usefulness, but also their differences in usages. Deciding between active RFID vs. passive RFID is really a matter of what goal needs to be met and what limitations are in place. Active can be read from further away and the tags are more durable, but they also have batteries that often cannot be replaced. Passive must be read from a shorter distance, but it’s also less expensive and the tags are typically more flexible. They are also less durable.

RFID technology, a form of Automatic Identification and Data Capture, gives many businesses the ability to track their assets more efficiently and in more detail. Radio waves provide flexibility and details that barcodes cannot.

What is RFID?

RFID is a technology used to transmit data stored in a tag.

What is the main difference between active and passive RFID?

The primary difference is whether or not a battery is needed – active RFID needs a power source, where passive does not.

Where can I find a passive RFID reader?

Check out our hardware capable of reading RFID, including the CR5400, AT9000, and the Panasonic N1.