Tracking Infrastructure

How Does An RFID Tag Work?

Posted by Jeff Pollock

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May 25, 2018 4:31:04 PM



RFID systems are becoming more and more prevalent. We drive through tolls and the RFID tag in our car is automatically read and we are charged. Tags are included on items in stores to deter shoplifting. Hospital equipment is tagged so that supplies can be tracked. And, of course, infrastructure products are being tagged at manufacture so that critical QC/QA information can be tracked throughout the product's life cycle. They are everywhere but... how does it actually work?

RFID stands for 'Radio Frequency Identification'. As the name implies, radio waves are generated between a scanner and the tag. The information held by the tag is communicated to the scanner through these radio waves. The scanner then transmits this information to a mobile device or computer via bluetooth, WiFi or cable.

There are two types of RFID tag: active and passive.

Active tags are the sexiest (to the extent that an RFID tag can be sexy) because they do the most. These are battery powered and 'hold memory'. This is the type that is used in tolls. When you pass through the toll, the scanner at the toll communicates with your transponder (containing an active RFID tag inside). Because the tag is active... always on... it holds a basic set of information about your account in much the same way a PC uses random access memory (RAM) when it is turned on. The upside of active tags is that they can do more because they can hold more information. The downside is that they naturally cost more.

Passive tags are used much more because they cost less and, due to their simplicity, have more applications. These tags contain an antenna and a very tiny integrated chip (called an IC in RFID parlance) that only holds a serial number. The signal from a scanner is received by the antenna and activates the IC which, in turn, returns a 24-digit serial number that was previously "written into" (programmed into) the IC. The antenna then returns this information to the scanner and the scanner distributes the serial number to a phone, tablet or computer with which it is paired.

Idencia uses passive tags because these are the least expensive and they serve well our need to provide each product with a unique serial number.

It could be (and often is) argued that RFID tracking is the precursor to the internet-of-things. (Before we ask 'things' to communicate with us, we need to be able to identify them.) This is why we refer to the concrete products tracked with Idencia as Connected Concrete... products that are serialized and digitally connected through a web-hosted account. Once products are serialized, managing them is much more simple... and powerful... using digital technology. If you want to receive some advice on implementation, check out: 5 RFID Implementation Tips.

About Idencia

Our purpose at Idencia is to offer precast RFID tracking solutions that improve productivity throughout the value chain. Our subscription offering applies to products from the time of manufacture through end-of-life. As a cloud-hosted product tracking system that is seamless between manufacturers, contractors and asset managers, Idencia adds information value to all, eliminates redundancy and saves time. If you would like to learn more, click below.


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Topics: Idencia Tips

About this blog

Tracking Infrastructure is a blog about innovation in the manufacture, construction and management of infrastructure.

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