How Do RFID Systems Work

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basic-rfid-system

The basic RFID model includes the following:

Tag

  • Tag chips or integrated circuits
  • Tag antennas

Reader

  • Reader antennas
  • Reader control and application software
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RFID Solutions

A basic RFID system has tags attached to all items that need to be tracked. Made from a tiny tag-chip, these tags are also known as integrated circuit (IC) and are connected to an antenna that can be built into various types of tags such as apparel hang tags, labels and security tags – but also industrial asset tags. In a nutshell, every tag chip contains memory that is stored in it and contains the basic product code (EPC) of the product and other necessary information allowing it to be tracked and identified by the UHF RFID scanner or reader everywhere.

On the other hand, the UHF RFID reader is a network-connected device which can either be fixed or mobile – and features an antenna that sends the power and receives signals as commands to the tags. In other words, it is an access point for RFID tagged items so that the tags data is made available to every business application.

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RFID Tags

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As we said above, an RFID tag is comprised of an integrated circuit called an IC or simply, a chip. This chip is attached to an antenna that is printer, etched, vapor-deposited or stamped onto a mount that is a polyethylene therephtate (PET) or a paper substrate. This combination of a chip and an antenna is called an inlay and is converted and put in between a printed label and its adhesive backing – or inserted in a durable structure.

Tag Chip

Also known as the integrated circuit, the tag chip is known for its performance, memory and extended features. It is a device that is pre-programmed with a tag identifier and a unique serial number that is assigned by the chip manufacturer. It also features a memory bank in order to store every item’s unique tracking identifier – known as a product code or EPC.

Electronic Product Code (EPC)

The electronic product code (or EPC) is stored inside the chip’s memory – printed by an RFID printer and taking 96-bit strings of data. Its first eight bits consist of a header that identifies the protocol’s version and the next 28 bits identify the organization that manages that tag’s data, assigned by the EPC global consortium. The following 24 bits present the object glass that identifies the type of product and the last 36 bits are reserved for the unique serial number for each particular tag. Usually, the last two fields are set by the organization that issued that tag.

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Tag Antennas

The tag antenna is a collector of energy that channels it to the chip in order to turn it on. The larger this antenna’s area is, the more energy it is capable of collecting and channeling – hence, the greater read range that the tag will have.

Basically, there isn’t a perfect fit of an antenna that works for all applications. The most important aspect is the application that defines its specifications. And while some tags are optimized for a particular frequency band, others can be tuned for stellar performance when attached to materials that do not work well wirelessly (liquids, metals etc.). An antenna can be printed, etched or stamped with conductive ink, or even vapor deposited onto labels.

Every tag having a single antenna is not as reliable as a tag with multiple antenna. Simply put, a single antenna can result in a ‘dead zone’ – an area where the signal is not strong or easily harvested to power on the chip. That is why multiple antennas are recommended – in order to eliminate any dead zones and increase the readability of the chip.

RFID Readers

rfid-readers

An UHF RFID reader is also known as an interrogator. It is simply a device that provides connection between the tag data and the enterprise system software needing the information. The UHF RFID scanner (or reader) is capable of communicating with tags that are within the field of operation and can seamlessly take care of the inventory, filter, write or encode selected tags.

The reader uses an antenna that is attached and able to capture data from tags. Afterwards, the data is passed to a computer so that it becomes processed. Similar to the RFID tags, there are multiple makes and models of UHF RFID readers in various sizes and types. They can either be fixed in a store or factory or integrated into a mobile device known as a handheld PDA with UHF RFID – or a handheld computer with UHF RFID.

Reader Antennas

As you may know by now, an UHF RFID scanner or reader is comprised of an UHF RFID reader and reader antennas that work together in order to read tags. The process is quite straightforward – the reader antennas convert the electrical current into electromagnetic waves which are radiated into space and from where they can be received by a tag antenna and afterwards converted into electrical current. Similar to the tag antennas, there is a vast array of reader antennas and selecting the best one varies mostly because of the solution’s specific application and environment.

The two most common types of reader antennas are linear and circular polarized antennas. In a nutshell, antennas that radiate linear electric fields have long ranges and high levels of power that enable their signals to penetrate through different materials in order to read tags. The linear antennas are however sensitive to tag orientation and depend on the tag angle or placement. Therefore, they can have a difficult time reading tags. Alternatively, the antennas that radiate circular fields are less sensitive to the orientation, but not able to deliver the same amount of power as linear antennas.

The choice of antenna is also determined by the distance between the tag and the UHF RFID reader. Also known as read range, this distance is operated by reader antennas in either a ‘near-field’ (short range) or ‘far field’ (long range). The near-field situation is less than 30cm where the antenna uses magnetic coupling – and the readability of the tags is not affected by the presence of dielectrics. On the other hand, far-field applications use a range that is greater than 30cm and can extend to tens of meters. This process is known as electromagnetic coupling and dielectrics can weaken its communication.

Reader Control And Application Software

The application software and reader control are both aspects of the middleware. The middleware is the platform onto which the UHF RFID readers and applications operate. It is also the backbone that sends the control commands to the reader and receives the tag data from it.

Creating An RFID Solution

Deploying an UHF RFID scanner or reader needs a lot of components and multiple actors. Technically, it is a system that requires basic hardware including the previously mentioned tag chips, antennas, readers and reader antennas – as well as the reader control and application software to complete the entire solution.

As soon as these components ‘click’ together, there are endless ways an UHF UHF RFID reader can be used – with a lot of creative applications possible. The RFID system applications are bound to improve the quality of many business operations, inventory and customer experience – and disrupt the traditional way of organizing and handling items.

RFID Devices

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BH9
UHF RFID
Scan distance 2-3 meters

Rugged-Industrial-tablet-BT77-700x7001

BT77
UHF RFID
Scan distance 2-3 meters or 5-7 meters


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