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Complete Guide to RFID Tracking
What is RFID?
Radio Frequency Identification (RFID) technology utilizes radio waves for contactless data transfer and identification of objects, animals, or humans. A standard RFID system consists of a reader, RFID tags, and antennas. This versatile technology sees widespread use in sectors such as healthcare, retail, hospitality, and manufacturing, offering a key advantage over barcodes by eliminating the need for line-of-sight scanning. This beginner's guide will explore the essentials of RFID, answering questions like its definition, the meaning behind the technology, its operational principles, and its diverse applications.
How Does RFID Work?
By embedding items with RFID tags, users gain the power to automatically and uniquely identify and track their inventory and assets. This is achieved through radio waves transmitted from an RFID antenna to nearby RFID tags. RFID readers play a crucial role by boosting energy, encoding it with data, and broadcasting it at a specific frequency through the antenna cable to the connected antenna.
The key to distinguishing individual items lies in the unique identifier stored within each RFID tag's memory. This allows for effortless differentiation between physically identical items with a simple scan.
RFID elevates automated identification technology by enabling tag readings without a direct line of sight and from distances exceeding 30 meters.
RFID Frequencies
Understanding RFID technology involves recognizing its operation across three key frequency ranges, each with distinct read ranges and specifications within the Electromagnetic Spectrum. These primary frequency bands for RFID transmissions are: Low Frequency (LF RFID), High Frequency (HF RFID), and Ultra-High Frequency (UHF RFID).
Low Frequency (LF) RFID
Operating in the range of 125-134 kHz, is characterized by its short read range, typically less than a foot, and its robustness in challenging environments. These lower frequencies exhibit a strong ability to penetrate non-metallic materials and are less susceptible to interference from liquids and metals. Commercially, LF RFID is widely utilized for animal identification tags (livestock and pets), access control systems (proximity cards), and industrial applications requiring reliable reads in harsh conditions. Its durability and ability to function in demanding environments make it a dependable choice for tracking and identification where close proximity reading is sufficient.
High Frequency (HF) RFID
Operating at 13.56 MHz, offers a moderate read range that can extend up to a few feet. This frequency band strikes a balance between read range, data transfer speed, and cost-effectiveness. HF RFID is a cornerstone of numerous commercial applications, including contactless payment systems (NFC), smart cards for access control and ticketing, library book tracking, and near-field communication (NFC) interactions with smartphones. Its ability to facilitate secure and convenient transactions and data exchange has made it a ubiquitous technology in everyday life.
Ultra High Frequency (UHF) RFID
Operating in the 860-960 MHz range, provides the longest read ranges among the primary RFID frequencies, often reaching tens of feet, and supports high data transfer rates and the ability to read multiple tags simultaneously. These characteristics make UHF RFID ideal for applications requiring efficient tracking over larger areas. Commercially, it is extensively used in supply chain management for inventory tracking in retail, warehousing, and logistics, asset management in large facilities, toll collection systems, and race timing. The long read range and bulk reading capabilities of UHF RFID significantly enhance efficiency and visibility in various industries.
Passive RFID Tracking Systems
Understanding RFID technology involves recognizing its operation across three key frequency ranges, each with distinct read ranges and specifications within the Electromagnetic Spectrum. These primary frequency bands for RFID transmissions are: Low Frequency (LF RFID), High Frequency (HF RFID), and Ultra-High Frequency (UHF RFID).
A complete passive RFID tracking system will consist of a combination of hardware and software systems.
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RFID Tags - These are the tags that are being attached to the assets you wish to track.
RFID Printers - For printing onto RFID Tags
RFID Readers - For reading the RFID Tags
RFID Software - The software system that drives all of the hardware
RFID Tags
At its core, passive RFID tags consist of two key components: an antenna, responsible for sending and receiving radio signals, and an integrated circuit (IC) or RFID chip, which holds the tag's unique identification and other relevant data. These tags are attached to items to enable tracking via an RFID reader and antenna system.
When an RFID reader emits radio waves, passive RFID tags (those without their own battery) harvest energy from this transmission. This energy flows through the tag's antenna to its chip, activating it. The chip then modulates the received energy with the stored information and transmits a signal back to the reader.
The data on an RFID chip is organized into four memory banks: EPC, TID, User, and Reserved. The EPC and User banks are programmable and can store unique identifiers or specific information about the tagged item. The TID bank holds immutable data about the tag itself, including its unique identifier. The Reserved bank is utilized for advanced tag functions like locking or memory expansion.
The market offers a diverse range of RFID tags in various shapes, sizes, and materials, each designed with specific features to optimize performance in different environments, on various surfaces, and for particular applications. Selecting the most appropriate tag for the intended use is crucial for achieving optimal tracking results.
RFID Tag Components
Every RFID tag has 3 main components​​​
RFID Chip - The RFID chip, also known as an integrated circuit (IC), is the "brain" of the RFID tag. It's a small electronic circuit that data storage, processing and logic, and communication protocols.
RFID Antenna - The antenna in an RFID tag serves as the crucial interface between the RFID chip and the external world of radio waves.
RFID Substrate - An RFID substrate serves as the base material onto which the components of an RFID tag are mounted or embedded. Think of it as the foundation of the tag.
RFID Tags or Labels?
The terms "RFID tag" and "RFID label" are often used interchangeably, however, there's a subtle distinction that often comes down to form factor and how they are applied.
RFID Tags
An RFID tag typically is packaged with a protective encasement around the various RFID components. RFID Tags come in many different forms:
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Metal Mount RFID Tags - These tags are specifically designed to be attached to or embedded in metallic surfaces. Standard RFID tags often have their performance severely degraded or become unreadable when placed on metal due to signal reflection and absorption. Metal mount tags incorporate shielding materials and antenna designs that counteract these effects, allowing for reliable reading.
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Ceramic RFID Tags - Encased in durable ceramic housings, these tags offer excellent resistance to harsh environments, including high temperatures, chemicals, and physical abrasion. The ceramic material also provides good electrical insulation and can be designed to optimize RF performance in certain applications.
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Hard Plastic RFID Tags - Encased in rigid plastic housings, these tags offer durability and protection against physical impact, moisture, and some chemicals. They come in various shapes and sizes and can be attached using screws, zip ties, or adhesives.
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Epoxy RFID Tags - The RFID chip and antenna are embedded in a rugged epoxy resin. This provides protection against moisture, dust, and physical stress. They can come in various shapes and thicknesses.
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Misc RFID Tags - Many other formats of RFID Tags can be found such as wristband, ear tags, bolt tags, as well as coin style RFID Tags.
RFID Labels
Example of Variety of RFID Tags
An RFID label is a specific type of RFID tag that has the form factor of a traditional adhesive label or sticker. RFID Labels are typically flexible and are usually adaptable to pairing with an RFID printer. RFID labels tend to be less expensive than RFID tags.
Print custom information on
RFID labels
Tag Selection is Critical
RFID tags can be found in a wide variety of sizes and constructs. From paper labels to ceramic tags, every type of tag has its own advantages and disadvantages.
The Tag Selection Process
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How much room do I have on my asset?
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What kind of material will I be applying the tag to?
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Do I need metal mount RFID tags?
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Do we need human readable on our tags?
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What kind of range do we need for our tags?
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Do our tags need to be able to survive extreme conditions such as high heat or solvents?
Contact Rocket RFID for Help Choosing Your RFID Tags
RFID Printers
RFID printers are specialized devices that combine traditional printing capabilities with the ability to encode RFID tags. These printers allow users to print human-readable information like text, barcodes, and graphics onto the surface of an RFID label or tag while simultaneously encoding the embedded RFID chip with relevant data, such as a unique identifier or product information. This dual functionality streamlines the process of tagging assets or inventory, ensuring both visual identification and electronic tracking are integrated into a single step. RFID printers are essential tools for businesses looking to implement or expand their RFID systems for improved inventory management, asset tracking, and supply chain visibility.
RFID printers come in 3 primary formats
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Mobile RFID Printers - These are printers that are designed to be portable, allowing printing from anywhere on the go.
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Desktop RFID Printers - This style or printer is designed for an office setting allowing a small to mid number of RFID tags to be printed.
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Industrial RFID Printers - More expensive and allowing for massive printing output. This kind of printer is designed for professional print shops.
How to choose which printer to buy?
Choosing the right RFID printer can be critical in the success of your RFID project. Some RFID printers may not have the specs that you require. For example, some types of RFID metal mount printable labels are only compatible with specific printer models. Other considerations:
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Printer Needs and Volume - Evaluate your required print volume and the types of information you need to print on the labels or tags. Consider the print resolution and speed offered by the printer to ensure it meets your operational demands.
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Label Compatibility and Size - Verify that the printer is compatible with the types and sizes of RFID labels or tags you intend to use. Check the printer's specifications for maximum and minimum label dimensions and material compatibility.
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Connectivity and Integration - Assess the printer's connectivity options (USB, Ethernet, Wi-Fi) and ensure it can seamlessly integrate with your existing computer systems, network infrastructure, and any RFID software you plan to use. Consider ease of setup and driver availability.
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Durability, Reliability, and Cost - Evaluate the printer's build quality and expected lifespan, especially if it will be used in demanding environments. Research user reviews and consider the total cost of ownership, including the initial purchase price, maintenance, and the cost of ribbons and other consumables.
Contact Rocket RFID for Help Choosing Your RFID Printers
RFID Readers
RFID readers provide the reading mechanism to give visibility to the tags that are placed on your assets and employees. Choose the right type of scanner for your workflow.
Mobile Readers
Mobile RFID readers enable users to scan tags and interact with software simultaneously, offering exceptional workflow flexibility. This allows for on-the-fly decision-making, empowering users to complete tasks with greater agility.
Mobile RFID readers come in 2 basic formats:
Integrated Mobile Reader
Sled Mobile Reader
Each style of mobile RFID reader has its own pros and cons:
Integrated Mobile Reader
Integrated mobile RFID readers have the RFID scanner and computer all integrated into one unit.
Advantages
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All-in-One Convenience: Combines the RFID reader, antenna, computing power (often a handheld computer or smartphone), and sometimes a barcode scanner into a single, purpose-built device. This reduces the number of separate components a user needs to carry and manage.
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Optimized Integration: Hardware and software are designed to work seamlessly together, potentially leading to better performance, power efficiency, and user experience compared to a modular setup.
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Ergonomics and Durability: Often designed with ergonomics in mind for comfortable single-handed operation over extended periods. They are also typically built to withstand the rigors of mobile use, including drops and exposure to environmental factors.
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Simplified Management: Managing and charging a single device is generally easier than managing multiple separate components. Software updates and configurations are also typically handled in one place.
Disadvantages
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Less Flexible Upgrades: Upgrading the RFID reading technology or the computing platform might require replacing the entire integrated device, which can be more costly than upgrading a single component in a sled system.
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Single Point of Failure: If the integrated device malfunctions, the user loses both the RFID reading capability and the computing interface.
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Higher Upfront Cost: Integrated readers can sometimes have a higher initial purchase price compared to just buying an RFID sled attachment for an existing device.
Sled Mobile Reader
Sled mobile readers have the RFID reader and mobile computer separated. They typically have a dock that the mobile computer or phone sits on and they often connect via Bluetooth to operate together.
Advantages
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Flexibility of Host Device: Sled readers attach to existing smartphones, tablets, or handheld computers. This allows organizations to leverage their current investments in mobile devices and choose devices with specific features that suit their needs.
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Modular Upgradability: The RFID sled can be upgraded or replaced independently of the mobile computer. This can be more cost-effective in the long run as technology evolves or if one component fails.
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Potentially Lower Initial Cost: If an organization already has compatible mobile devices, the initial investment might be lower as they only need to purchase the RFID sled.
Disadvantages
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Bulkier and Less Integrated: The combination of a sled and a separate mobile device can be bulkier and less streamlined than an integrated reader, potentially making it less comfortable for prolonged use.
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Potential for Connectivity Problems: Communication between the sled and the host device can sometimes experience connectivity issues.
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Increased Management Overhead: Managing and charging two separate devices can add to the overall management burden. Software integration between the sled and the host device might require additional configuration and maintenance.
Fixed RFID Readers
Fixed RFID readers are designed for permanent installation, typically mounted on walls or ceilings. These readers feature ports for connecting external RFID antennas, extending their coverage area. Integrated fixed readers combine the reader unit and RFID antennas into a single, self-contained device. RFID tracking becomes active automatically whenever an RFID tag enters the reader's detection zone.
Fixed RFID readers come in 2 basic formats:
Standard Fixed Reader
Integrated Fixed Reader
Standard Fixed Reader
Standard fixed RFID readers are characterized by their separate components: the reader unit itself and the need for external RFID antennas to be connected via coaxial cables to antenna ports on the reader. Things to consider with a standard fixed RFID reader:
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Antenna Placement Flexibility: Consider the layout of your environment and the desired read zones. Standard readers offer the advantage of strategically placing antennas at various locations and orientations, allowing you to customize coverage for complex or large areas, potentially maximizing read accuracy and range.
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Scalability and Expansion: Think about future growth and potential changes to your tracking needs. The ability to add or relocate antennas connected to a standard reader provides greater scalability and adaptability as your requirements evolve.
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Cable Management and Installation Complexity: Be mindful of the need to run coaxial cables from the reader unit to each antenna. This can involve planning for cable pathways, potential cable clutter, and the added complexity of installation and maintenance.
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Antenna Selection and Optimization: Recognize that you will need to select appropriate antennas based on your specific application (e.g., near-field, far-field, specific polarization). Understanding antenna characteristics and optimizing their placement is crucial for achieving desired performance.
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Individual Component Maintenance: While modularity offers flexibility, it also means that troubleshooting and maintaining separate reader and antenna components might require more individual attention compared to an integrated solution.
Integrated Fixed Reader
Integrated fixed RFID readers streamline deployment by combining the reader unit and one or more RFID antennas into a single, self-contained enclosure. Things to consider when thinking about choosing an integrated fixed RFID reader:
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Simplified Installation: The all-in-one design significantly simplifies installation as there's no need to mount separate antennas and run coaxial cables back to the reader. This can save time and reduce installation costs, especially in deployments with fewer read points.
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Pre-Optimized Performance: Integrated readers often have antennas that are specifically designed and optimized to work with the internal reader components. This can lead to predictable and reliable performance without the need for extensive antenna tuning or placement experimentation.
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Limited Flexibility in Antenna Placement and Coverage: The integrated nature means that the antenna placement and coverage area are fixed based on the reader's design. This can be a limitation if you need to cover a large or irregularly shaped area, or if you need to position antennas in specific, distant locations.
Need help choosing which RFID reader is right for your project?
RFID Antennas
RFID antennas are essential components of an RFID system, acting as the bridge between the RFID reader and the RFID tags. Their primary function is to transmit radio frequency energy emitted by the reader to the tags and, conversely, to receive the RF signals transmitted back by the tags. The design, size, and gain of an RFID antenna directly influence the read range, read rate, and overall performance of the RFID system.
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Different antenna types are available, each optimized for specific application requirements, and environmental conditions, allowing for tailored solutions for various tracking needs.
Antenna Polarization
RFID antennas are often categorized by their polarization, the manner in which they transmit RF waves. Linear polarization involves waves oscillating in a single plane (vertical or horizontal), whereas circular polarization involves waves rotating in a circular fashion.
Linear Polarized Antenna
Circular Polarized Antenna
Why does polarization matter?
Choosing the best antenna polarization can make or break an RFID project.
Linear antenna polarizations
Linear polarized antennas are very good at reading tags that are oriented the same angle as the RFID antenna. All of the antenna energy is going to be put into reading in that one direction. Tags that are oriented with the antenna will offer superior reads while tags that are not oriented with the antenna may not be read at all.
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Circular antenna polarizations
Circular polarized antennas are able to read RFID tags of all different orientations with moderate range. The antenna RF is spread out so you give up some of the superior range that you might see with a linear polarized antenna.
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Ultimately choosing the right antenna is dependent upon understanding how the tags will be arranged in your environment. Tags that are attached to boxes on a shelf all facing one direction might indicate a linear antenna. Tags scattered throughout an office space oriented in all different directions would be best served with a circular antenna.
Antenna Gain
A key performance characteristic of Ultra-High Frequency (UHF) Radio-Frequency Identification (RFID) antennas is gain. This metric describes the antenna's ability to enhance signal strength in a specific direction, both when sending out radio frequency energy and when receiving signals. Expressed in decibels (dB), often relative to an isotropic radiator (dBi), higher gain signifies a more focused and powerful beam of RF energy, leading to improved read distances in that direction.
Why does gain matter?
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Range and Coverage: Greater gain in RFID antennas translates to extended signal reach for both transmission and reception, a vital attribute for covering large areas like warehouses, logistics yards, and retail floors.
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Directionality: Antenna gain directly impacts its directionality. High-gain options offer focused signal projection, enabling targeted read zones and reduced interference.
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Signal Strength and Reliability: Higher gain amplifies signal strength, leading to more reliable and accurate RFID tag readings, especially in environments with obstacles or interference.
Other considerations
Aside from polarization and gain, various other features should be considered when evaluating an RFID antenna for a project:
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Beamwidth: The beamwidth describes the angle of the antenna's effective radiation pattern, both horizontally and vertically. A wider beamwidth covers a broader area but with less concentrated power, resulting in a shorter read range compared to a narrow beamwidth antenna with the same gain. Choose a beamwidth that matches the physical area where you expect tags to be present.
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Environment and Mounting: Consider the environment where the antenna will be deployed. Will it be indoors or outdoors? Will it be exposed to weather, dust, or moisture? Choose an antenna with an appropriate IP rating and construction materials. Also, consider how the antenna will be mounted (wall, ceiling, pole) and select an antenna with suitable mounting options.
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Physical Size and Aesthetics: The physical size and appearance of the antenna can be important, especially in customer-facing environments. Consider whether a discreet, low-profile antenna is needed or if a larger, higher-gain antenna is acceptable. Ensure the size and weight of the antenna are compatible with your mounting structure.
Choosing the right antenna can be the hardest part of an RFID project. Let our experts guide you.
RFID Software
Choosing the right RFID software is just as important as choosing the right hardware. The RFID software will work with all of the hardware and provide the user interface and workflows needed for your RFID project.
Common Workflows for RFID
Periodic Inventory
One of the most common tasks used with a handheld RFID scanner is periodic inventory. Handheld scanners are especially useful for this task:
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Software shows exactly what is expected in each room.
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User can walk around scanning to rapidly inventory all room assets
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Gives user flexibility to handle edge cases such as assets showing up in wrong room, missing, etc.
RFID speeds up periodic inventory
Checkout Operations
Another ideal workflow for RFID handheld scanners is checkout and checkin.
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Scan employee RFID badge to start checkout operation.
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Scanner rapidly reads all assets that user needs to take custody of.
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Rocket Tracked software monitors all checked out assets and enforces checkout duration thresholds.
Supply Chain and Logistics
RFID tags attached to goods, pallets, and containers enable real-time tracking throughout the supply chain, from manufacturing to distribution and retail.
This improves visibility, reduces delays and errors, optimizes warehouse operations, and enhances overall supply chain efficiency.
Work-in-Process (WIP) Tracking
In manufacturing environments, RFID tags attached to components or assemblies allow for real-time monitoring of the production process. This helps track the progress of goods, identify bottlenecks, optimize workflows, and improve quality control.
