Radio frequency identification transponder with antenna high integrated on the smart label

An Introduction to RFID Tracking

The topic of RFID Tracking involves a lot of details in order to fully understand the different features. 

What is RFID?

Radio Frequency Identification (RFID) involves using radio waves as a medium to communicate information between different systems. The hardware systems involve one or more transmitters and receivers to facilitate RFID tracking.

Frequency Ranges

LF 120-150kHz - Primarily used for animal identification.

  • Range is approximately 4 inches

HF 120-150kHz - Used by Smart Cards

  • Range is 4 inches to 3 feet

UHF 433MHz - Used for Active RFID tags

  • Range is 3 to 300 feet

UHF 915MHz - Primary frequency range for passive RFID tags

  • Range is 3 to 30 feet

Microwave 2.4GHz - 5.8GHz - Wi-Fi, Bluetooth, Active RFID

  • Range is 3 to 300 feet

Microwave 3.1GHz - 10GHz - High speed data transmissions, amateur radio.

  • Range varies greatly

Radio Freqauencies

How does RFID Work?

RFID tracking systems can be divided into two distinct groups of either passive RFID or Active RFID.

Passive RFID

Passive RFID is an RFID tracking system that uses RFID tags that don't have batteries built into them. Instead an RFID reader is required to be in range of the tag in order to facilitate communication.

  • Read range is from 1 to 30 feet

  • Tags communicate in the 915MHz frequency range

Because RFID tags are not powered by battery, there are many more types of applications that they can be applied to in order to enable RFID tracking.

  • Document tracking

  • Personnel monitoring

  • Asset location tracking

  • Tool tracking

  • Periodic asset inventories

  • Shipment logistics tracking

  • Warehouse inventory management

  • Many more

Active RFID

Active RFID is an RFID tracking system that uses RFID tags that have batteries built into them. The tags don't have to be in range of an RFID reader in order to be powered. This opens up the technology to many more applications.

  • Asset location tracking

  • Laydown yard monitoring

  • Work in progress tracking

  • Personnel monitoring

  • Temperature sensitive applications such as food and drug monitoring

  • Shipping yard monitoring

  • Mustering applications.

Passive RFID Hardware

Passive RFID is a highly standardized technology platform. As a result, there is a collection of standard hardware that can be utilized by a passive RFID tracking system. 

RFID Tag

The RFID Tag is the single most important component of a Passive RFID Tracking system. Various other hardware component choices can be made with Passive RFID, but any Passive RFID Tracking system will always have Passive RFID tags.

RFID Tag, RFID Label, RFID Inlay - What is the difference

Passive RFID can be packaged in a couple of different ways depending on the industrial needs.

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The minimal components needed for Passive RFID Tracking tags are:
  • RFID Chip - This is the processor unit for the tag

  • RFID Antenna - The antenna picks up RF signals which is used to power the chip so that it can respond.

  • Substrate - This is the material that the chip and antenna are placed upon.

When only these 3 components are added to the system, it is referred to as an RFID Inlay. There is no label or plastic incasing. Additional components can be added to provide different industrial packaging:

  • RFID Label - The adhesive is placed within a material like a paper label. This allows custom information to be printed upon the tag to provide human readable information. RFID Labels are often paired with RFID Printers in a custom environment.

  • RFID Tag- When extra protection is required, an RFID protective encasement can be used to ruggedize the components as well as provide special properties to adjust to the material that the Passive RFID tag will be attached to.

Metal Mount Tags

Trying to place a standard RFID paper label tag onto a metal asset will change the operating properties of the antenna, shorting out the RFID. To address this, manufacturers create special Metal Mount RFID tags that are designed to be affixed to metal objects.

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RFID Tag Performance

RFID tracking tags have a wide variety of performance characteristics ranging from only 1 foot  up to 30 feet or so. This wide variation is largely influenced by the size of the tag.

A general rule of thumb is that the smaller the RFID tag, the smaller the expected read range. These numbers correlate with manufacturer specifications as well as real-world data.

  • Smaller isn't always better.

  • It is important to carefully match the space constraints of your assets when selecting your RFID tags.

  • Beware of metal - Remember that special Metal Mount tags must be used when applying to metal products. Some assets, such as laptops, may have a surface that looks plastic, but in reality uses a metal-composite material which regular RFID Tags won't work on.

RFID Readers

A Passive RFID Tag will not work for RFID tracking until it is powered by an RFID Reader. Various kinds of RFID Readers exist each tailored for specific applications.

Mobile Readers

Mobile Readers are handheld readers with RFID built into them. They are typically configured as an RFID gun where you pull the trigger to start reading RFID tags nearby. Mobile readers enable RFID tracking at any location. Mobile readers excel at:

  • Periodic inventories

  • Asset Location discovery

  • Rapid checkout operations

  • Tool crib management 

Mobile Readers come in two basic configuration options:
  • Integrated Mobile Reader - The mobile unit is integrated into a single unit. These readers often have docking stations which they can be slotted into to ensure the unit is always fully charged when you pick it up.

  • Sled Mobile Readers - These mobile units consist of the RFID gun part of the reader with an additional mobile computer piece that is used to drive the RFID gun component. Sled units tend to be less expensive, but you have to worry about running out of battery with two different hardware components.

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Integrated Mobile Reader

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Sled Mobile Reader

Fixed Reader

Fixed Readers are designed to be mounted on a wall or ceiling to enable RFID tracking at a specific location. Fixed Readers have ports where RFID Antennas can be attached.

  • Different readers have a different number of ports. Typical configurations are two or four port readers.

  • Fixed Readers typically provide drivers to interface with the hardware.

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4-port Impinj Fixed Reader

Integrated Fixed Reader

Integrated Fixed Readers consist of the RFID Reader and antennas all combined into a single finished package. 

  • Number of RFID Antennas is fixed

  • Provides a sleek, finished product ready to mount in any environment.

  • Some Integrated Fixed Readers hardware profiles have been optimized for maximum effectiveness.

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Impinj X-Span Integrated Fixed Reader

RFID Antennas

RFID Antennas are the components that actually transmit and receive RF signals within the Passive RFID system. RFID antennas provide specification parameters for their RF, but they basically come in two flavors:

  • Circular polarization - These antennas emit RF in a corkscrew fashion. Because they broadcast RF in two planes, they don't have the same range as linear polarization antennas.

  • Linear polarization - Linear polarization antennas emit RF polarized in a single plane. They provide the best range.

Linear antennas should be chosen when you are very sure about your environment and the antenna and tag will be aligned with each other. In environments where the RFID tag can be aligned any orientation, circular antennas are best.

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Vulcan RFID Antenna

RFID Antenna Cables

Antennas need to be connected to the RFID Reader with an RFID cable. These are coaxial cables that are essential to connect these two systems together. When selecting an RFID antenna, you need to consider 3 different properties:

Cable Length
  • RFID cables come in a variety of different cable lengths.

  • The longer the cable length, the worse the signal. It is best to choose the right length for your environment.

Insulation rating
  • Different cables have different insulation ratings. Insulation helps protect the signals from interference.

  • Insulation rating is especially important in harsh environments and longer cable runs.

Connectors
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  • At the end of each RFID cable, is a connector used to connect the RFID Reader and the RFID Antenna.

  • There are 6 major connector types. It is important to make sure that you are buying cables that will operate with your equipment.

RFID Cable Example

RFID Printers

Remember that RFID Labels are paper labels that encapsulate the RFID Inlay. RFID Printers are designed to print human readable information on these labels as well as the capability of programming the RFID tag for RFID tracking.

RFID printers come in three primary formats
  • Mobile RFID Printers - These are printers that are designed to be carried around, allowing printing on the go.

  • Desktop - Designed to be used in office type settings. These printers allow for a small to mid number of RFID tags to be printed.

  • Industrial - Industrial RFID Printers are designed for high volume printing of RFID tags. This type of printer would only be appropriate if printing more than 10,000 RFID tags per day.

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Zebra ZT421 Desktop RFID Printer

Choosing the right combination of RFID Labels and RFID Printer is very important. Some RFID tags will only work with some RFID Printers. 

Active RFID Hardware

Active RFID comes in many different variations. Choosing the right Active RFID hardware depends mostly upon what is needed for RFID tracking. InfinID Technology provides 3 primary variations of Active RFID products

V-Tag Active RFID Tags

​V-Tag is an RTLS Active RFID tag that allows for tag-to-tag communication through a mesh network.

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Setting up similar RFID tracking capabilities in a Passive RFID system would require wiring up Passive Fixed Readers anywhere you want to enable tracking. Passive Fixed Readers can cost more than $2,000 per reader which makes tracking many location cost prohibitive.

With V-Tag, you simply need to stick a $40 Fixed Location tag anywhere you want to enable location tracking. No need to run wires. The mesh network takes care of everything automatically. RFID tracking made easy.

V-Tag has on-board sensors

Every V-Tag has sensors on-board which can be used to monitor important assets. Automated alarms can be triggered when sensors go out of adjustable ranges. So many more applications have been opened up for RFID tracking.

  • Min and Max temperature - If the asset gets too hot or cold.

  • Shock - If the asset is dropped and experiences sudden acceleration.

  • V-Tag has an impressive battery of 6 years for the standard tag but when the battery is running low, it will let you know.

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Want to learn more about V-Tag?

V-Tag GPS RFID Tags

V-Tag GPS is a cutting edge Active RFID tag with a range of almost 4 square miles designed for outdoor RFID tracking.

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The most cost effective GPS asset tracking tag on the market

  • Traditional GPS tags require a monthly subscription. For every single tag.

  • V-Tag GPS saves money. No need for a monthly subscription anymore. V-Tag GPS allow for a rapid ROI.

Want to learn more about V-Tag GPS?

V-Tag Beacon Tags

The biggest advantage is in form factor and battery life. Since the V-Tag Beacon tag doesn’t participate in the mesh network, it requires a much smaller battery than a regular V-Tag.

  • V-Tag Gateway units are installed at each spot where you want to enable location RFID tracking.

  • The closest Gateway is identified as the winner Gateway and automatically updates the tag's Gateway location.

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Passive RFID Strengths for RFID Tracking

There is no single RFID system that is better than another. Instead, some systems are more appropriate for certain applications. Here are some Passive RFID tracking strengths:

  • Tags are very inexpensive. For applications that require tens of thousands of tags or more, Passive RFID usually wins out over Active RFID for RFID tracking due to budget limitations.

  • No need for battery - Never need to swap out a battery is one less thing to budget man-hours for.

  • Tags can be ruggedized - Passive RFID tags can be ruggedized for very hostile environments. Ceramic RFID tags can operate in very hot environments. Other RFID Tags can be constructed to tolerate harsh solvents as well as waterproof.

Active RFID Strengths for RFID Tracking

  • Read range - With a read range of up to 300 feet indoors and several square miles outdoor.

  • On-Board Sensors - open up many applications that would be impossible with Passive RFID.

  • Better reliability - Complex environments can be tricky for RTLS with Passive RFID systems. Active RFID provides for better reliability which fits complex, hard-to-track very well.

Have questions about RFID Tracking? Contact our RFID Experts.