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How Do RAIN RFID Systems Work?

There are three main elements to a RAIN RFID solution: tags, readers, and software. Here’s how it all works, and how our partners optimize all the parts.


What are the main elements of an RFID system?

RAIN RFID solutions include three main elements:

  • Tags: Tiny tags, containing a battery-free RAIN RFID tag chip and an antenna, are attached to items and contain identifying information about them. These tagged items are often referred to as endpoints.
  • Readers: RAIN RFID readers — which can be fixed or handheld — wirelessly access and read those tags, then communicate that data to system software. These edge devices can also write new data to the tags. 
  • Software: RAIN RFID software aggregates and transforms data from the endpoint reads, and delivers real-time information to enterprise and consumer applications. With this data, businesses can increase revenue, automate operations, improve customer experiences, and much more.

What are RAIN RFID endpoints?

In a basic RAIN RFID system, tags are attached to all items that are to be tracked. A RAIN RFID tag comprises a tag chip (sometimes called an integrated circuit, or IC) attached to an antenna that has been printed, etched, stamped, or vapor-deposited onto a surface — often a paper substrate or polyethylene terephthalate (PET). The chip and antenna combo, called an inlay, is then converted into or sandwiched between a printed label and its adhesive backing, or inserted into a more durable structure. 

Finished tags are available in a wide variety of shapes and sizes, including labels or stickers, hangtags, fabric tags, security tags, and industrial asset tags used on pallets and heavy machinery. Advancements in RAIN RFID have made it possible to tag metals and liquid containers, which can cause radio interference or signal degradation. 


How do RAIN RFID tags identify items?

RAIN RFID tag chips are pre-programmed with a tag identifier (TID), which is a unique serial number assigned by the chip manufacturer, and include a memory bank to store an item’s unique tracking identifier (called an electronic product code, or EPC). The chips don’t require batteries, and instead get power from the radio waves emitted by a RAIN RFID reader. The chips can be read from as far away as 30 feet (about 10 meters) without direct line-of-sight, and each chip costs just pennies.


What is an electronic product code (EPC)?

The electronic product code (EPC) stored in a tag chip's memory typically takes the form of a 96-bit string of data. The first eight bits are a header that identifies the version of the protocol. The next bits identify the organization that manages the data for this tag. Then there is an object class or item reference, identifying the exact type of product the tag is attached to. And the last group is a unique serial number for that particular tag. The whole EPC number can also be used as a key into a global database for uniquely identifying that particular product.


Why don’t RAIN RFID tags need batteries?

When a RAIN RFID reader emits radio waves to access and read a tag chip, the tag’s antenna collects some of that radio energy and channels it to power the chip.. Generally, the larger the area of the tag antenna, the more energy it will be able to collect and the greater read range the tag will have.

There is no perfect tag for all applications. It is the application that defines the specifications of the tag’s antenna specifications. Some tags might be optimized for a particular frequency band, while others might be tuned for good performance when attached to materials that typically may not work well for wireless communication (for example, certain liquids and metals). Made from a variety of materials, antennas can be printed, etched, or stamped with conductive ink, or even vapor-deposited onto labels.

Taking inventory with a RAIN RFID handheld reader is 25x faster than with a barcode reader.

Faster than barcode

How do RFID readers identify items?

RAIN RFID readers and gateways are edge devices that wirelessly power and communicate with tags, and deliver tag data to system software. Readers can be fixed or handheld, and communicate bi-directionally with endpoints that are within their range.  People and businesses can use readers to perform any number of tasks, including simple continuous inventorying, filtering for tags that meet certain criteria, writing (or encoding) selected tags, and more.

RAIN RFID readers can identify and locate more than 1,000 tagged items per second, without direct line-of-sight. Gateways integrate stationary readers with scanning antennas to locate and track tagged items. Impinj reader chips are designed to be embedded in handheld readers, smart vending machines, automobiles, mobile devices, printers and more.

Stationary readers require an antenna that sends power along with data and commands to endpoints. Since these readers are often used in automated applications, they can support additional connections, such as stack lights to notify users of completed reads. Readers and gateways are connected to a host PC or network to transmit all of the tag data.

What determines the range of an RFID system?

RAIN RFID readers work together with reader antennas to power and read tags. Reader antennas convert electrical current into electromagnetic waves, which can be received by tag antennas and converted back to electrical current. Just like tag antennas, there is a variety of reader antennas, and selecting the right antenna depends on a solution’s specific application and environment.

A main factor is the distance between the RAIN RFID reader and the tags it needs to read, or the read range. Reader antennas operate in either a near-field (short range) or far-field (long range) configuration. In near-field applications, the read range is less than 30 cm and readability is not affected by the presence of dielectrics, such as water or metal. In far-field applications, the range can extend up to several tens of meters, but dielectrics can weaken communication between the reader and tags.

Unlike barcodes, RAIN RFID tags can be read without direct line-of-sight — even through boxes or containers.

What software do RAIN RFID solutions use?

Many RAIN RFID readers use a standardized language called Low Level Reader Protocol, or LLRP. Software that resides specifically on a hardware component is called firmware, and it controls the operation of the device and does not typically initiate communication with external devices.

External application software sends control commands to readers and receives data from them, giving businesses access to all the information collected from tags. This software can manage reader health, perform remote firmware updates, and configure reader infrastructure — and enables businesses to integrate real-time, highly accurate RAIN RFID data into multiple business applications.


How can I easily implement a RAIN RFID solution?

The technology may seem complex and the options overwhelming, but the basics of any RAIN RFID system remains the same. 

  1. Tag chips provide unique identifiers and important information to help businesses. 
  2. Readers power tag chips and collect data from them, and also write new data to them.
  3. Software connects these RAIN RFID systems to computers or enterprise applications, so users can view data, receive alerts, and run their businesses better.

You don’t need to learn all the techincal aspects — our partners make it easy for businesses to deploy and optimize RAIN RFID systems. You can visit the Impinj Partner Directory to find the right solution provider for you. Or, reach out to us, and we can walk you through the process.

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